Error Code Reference

Understand, diagnose, and resolve errors that occur during workflow execution.

EW-FLOW uses numeric error codes organized by category. These codes appear on the Logs page and in Session Details when something goes wrong. Each error code belongs to a category identified by its numeric range, making it easy to determine which subsystem produced the error.

How error codes work

Field	Description
Code	Numeric identifier the unique error ID (e.g., `4001`)
Name	Machine-readable short name (e.g., `ModuleException`)
Category	The subsystem that produced the error (e.g., Module, Token, Flow)
Severity	Impact level Info, Warning, or Error
Description	Human-readable explanation of what went wrong
Resolution	Steps the user can take to resolve the issue

Generic (0xxx)

General errors that do not belong to a specific subsystem.

Code	Name	Severity	Description	Resolution
0000	Generic	Error	An unclassified error occurred.	Check the error message for details. If the issue persists, contact support.

Other (1xxx)

Errors related to Process and Channel resolution.

Code	Name	Severity	Description	Resolution
1001	ProjectNotFound	Error	The requested Process could not be found.	Verify the Process exists and is deployed to the correct Environment.
1002	ChannelNotFound	Error	The communication Channel could not be resolved.	Check that the Channel is properly configured in the Environment settings.

Flow (2xxx)

Errors that occur during the workflow execution flow Token movement, node traversal, and loop detection.

Code	Name	Severity	Description	Resolution
2001	OnGetNextNode	Error	Failed to determine the next node in the Process.	Verify that all nodes have valid outgoing Sequence Flows in the editor.
2002	LoopLimit	Warning	The workflow exceeded the maximum allowed loop iterations.	Review your Process for unintended loops. If a legitimate workflow needs more iterations, contact support.
2003	SessionAlreadyEnded	Warning	An operation was attempted on a Session that has already stopped.	No action needed the Session has completed. Start a new Session if required.
2004	RunIgnoredAwaitingTaskCallback	Info	Execution was skipped because the workflow is waiting for an external Task callback.	Ensure the external system sends the expected callback to the Environment URL.
2005	ReportNotFound	Error	The requested execution report could not be found.	Verify the Session ID is correct. The report may have expired based on your Service Plan retention.

Task (3xxx)

Errors related to Task resolution and data within BPMN nodes.

Code	Name	Severity	Description	Resolution
3001	TaskNoData	Error	A Task node was reached but contains no configured data.	Open the Process Editor and configure the Task's properties.
3002	TaskNotImplemented	Error	The Task type exists but has no execution handler.	Ensure the required Module is installed from the Marketplace.
3003	TaskNotFound	Error	The referenced Task could not be found in the Process definition.	Re-deploy the Process. If the issue persists, verify the BPMN file integrity.
3004	TasksWithSameId	Error	Two or more Tasks share the same identifier.	Open the Process Editor and ensure each Task has a unique ID. This usually requires recreating duplicate nodes.
3005	TaskInvalidData	Error	The Task's configured data is malformed or invalid.	Open the Task in the Process Editor and verify all required properties are set correctly.

Module (4xxx)

Errors originating from Module execution the most common category during runtime.

Code	Name	Severity	Description	Resolution
4001	ModuleException	Error	An unhandled exception occurred inside a Module during Task execution.	Check the error message for details. Verify the Module's Environment configuration.
4002	MissingServiceId	Error	The Module could not resolve the service identifier for the Task.	Re-deploy the Process. If the issue persists, reinstall the Module from the Marketplace.
4003	ServiceConfigurationError	Error	The Module's Environment configuration is invalid or incomplete.	Go to Environments and verify all required configuration fields for this Module are filled in.
4004	ModuleMissingService	Error	The execution service for this Task is not registered.	Ensure the Module is installed for this Process in the Marketplace.
4005	ModuleMissingNodeData	Error	The Task node has no data attached to it.	Open the Process Editor and configure the Task's properties.
4006	ModuleGenericException	Error	A generic error occurred within a Module.	Check the error message for specifics. Review Module configuration and Task properties.
4007	ModuleMissingServiceInterface	Error	The Module is missing a required service interface registration.	This is typically an internal issue. Contact support if the Module was recently updated.
4008	ModuleMissingConfiguration	Error	The Module requires Environment configuration but none was found.	Go to Environments, select the Environment, and fill in the Module's configuration. Look for the "missing" tag.
4009	ModuleInputEmpty	Warning	A Module Task expected input but received an empty value.	Verify that previous Tasks in the workflow are setting the expected Session variable.
4010	ModuleInputNotInSession	Warning	The variable referenced by the Task does not exist in the Session data.	Check that the variable name in the Task matches what was set by a previous Task. Variable names are case-sensitive.
4011	ModuleInvalidInput	Error	The input provided to the Module Task is in an unexpected format.	Verify the data type and format of the Session variable being passed to the Task.
4012	ModuleInvalidData	Error	The Module Task's internal data is corrupted or unparseable.	Re-configure the Task in the Process Editor and re-deploy.
4013	ModuleLog	Info	An informational log entry produced by a Module (not necessarily an error).	Review the message this may be diagnostic output rather than a failure.
4014	ModuleNotFound	Error	The referenced Module is not installed in this Process.	Install the required Module from the Marketplace for this Process.
4015	ModuleProcessorNotFound	Error	The Module's Task processor could not be located.	Re-deploy the Process. If the issue persists, contact support.
4020	WebhookSignatureInvalid	Error	An incoming webhook request failed its signature check and was rejected.	Verify the shared secret in the Module's Environment configuration matches the secret configured on the sending system, and that the request body is sent unmodified.
4021	OtpNotApproved	Warning	A one-time passcode (OTP) verification returned a non-approved status the code was wrong, expired, or the maximum attempts were exceeded.	Ask the user to re-enter the code or request a new one. Route the verification Task's `error` output to a retry branch in your Process.
4022	ModuleLogWarning	Warning	A warning-level log entry produced by a Module. A `Log` Task with Severity `Warning` also flags the execution as exceptional without stopping it; a `SetTagTask` whose tag could not be used (empty, reserved, or cut to 100 characters) only writes the entry.	Review the message execution continued, but something warranted attention.
4023	ModuleLogError	Error	An error-level log entry produced by a Module (e.g. a `Log` Task with Severity `Error`). Stops the Token.	Review the message and the Process branch that emitted it.

Token (5xxx)

Errors related to the execution Token the pointer that moves through your Process.

Code	Name	Severity	Description	Resolution
5001	TokenNotFound	Error	The execution Token could not be found.	The Session may have expired or been corrupted. Start a new Session.
5002	TokenAlreadyStopped	Warning	An operation was attempted on a Token that has already stopped.	No action needed the Token completed its path. Start a new Session if required.
5003	ErrorCreatingToken	Error	Failed to create a new execution Token for the Session.	Re-deploy the Process and try again. If the issue persists, contact support.
5004	TokenNotFoundInSession	Error	The Token was expected in the Session but could not be located.	The Session may be in an inconsistent state. Start a new Session.
5005	RootExecutionInvalid	Error	A child workflow was started with a parent Session reference that does not exist or belongs to a different Workspace.	Ensure the handler workflow and the Session that starts it are deployed in Environments of the same Workspace, and that the parent Session still exists.

Process (6xxx)

Errors related to Process definition, deserialization, and deployment validation.

Code	Name	Severity	Description	Resolution
6001	ProcessIsNull	Error	The Process definition is null or missing.	Re-deploy the Process from the editor.
6002	ProcessDeserializationError	Error	The Process BPMN data could not be parsed.	The Process file may be corrupted. Try opening a previous version from Process History.
6003	ProcessNotFound	Error	The referenced Process does not exist.	Verify the Process exists in the current Workspace. It may have been deleted.
6004	ProcessDuplicatedPool	Error	Two or more Pools in the Process share the same identifier.	Open the Process Editor and ensure each Pool has a unique name/ID.
6005	TaskDuplicated	Error	A Task ID appears more than once in the Process definition.	Open the Process Editor and remove or recreate the duplicate Task.

Session (7xxx)

Errors related to Session lifecycle creation, updates, and lookups.

Code	Name	Severity	Description	Resolution
7001	SessionNotFound	Error	The requested Session does not exist.	Verify the Session ID. It may have been purged based on your Service Plan retention.
7002	SessionUpdateError	Error	Failed to update the Session's state.	Retry the operation. If the issue persists, contact support.
7003	SessionNotCreated	Error	A new Session could not be created.	Check that the Process is deployed and the Environment is active.

Environment (8xxx)

Errors related to Environment resolution, configuration, and deployment targets.

Code	Name	Severity	Description	Resolution
8001	EnvironmentNotFound	Error	The referenced Environment does not exist.	Verify the Environment exists and has not been deleted.
8002	EnvironmentNotActive	Warning	The Environment exists but is currently disabled.	Go to Environments and set the Environment status to active.
8003	EnvironmentConfigurationNotfound	Error	Module configuration for the Environment is missing.	Go to Environments and fill in the missing Module configuration (look for the "missing" tag).
8004	EnvironmentNoVersionFound	Error	No Process version has been deployed to this Environment.	Deploy a Process version to this Environment from the Process Editor.
8005	ProcessVersionNotFoundInEnvironment	Error	The specific Process version could not be found in this Environment.	Re-deploy the Process. The version may have been overwritten.
8006	InvalidShortUrl	Warning	The short URL used to reach the Environment is invalid.	Verify the URL matches the one shown on the Environments page.
8007	RedisSaveFailure	Error	Failed to save Session state to the cache.	This is usually a transient issue. Retry the operation. If persistent, contact support.
8008	ProcessVersionNotFound	Error	The Process version reference could not be resolved.	Re-deploy the Process from the editor.
8009	NoTransport	Error	No communication transport is configured for the Environment.	Ensure the Environment has a valid Channel configured.
8010	TaskNoPaths	Error	A Task in the Process has no outgoing Sequence Flows.	Open the Process Editor and connect the Task to the next element.
8011	NoPathsInProcess	Error	The Process has no Sequence Flows defined at all.	Open the Process Editor and connect your elements with Sequence Flows.
8012	StartTaskNotFound	Error	The Process does not contain a Start Event.	Open the Process Editor and add a Start Event node to your Process.
8013	TasksHasNoType	Error	A Task in the Process has no type defined.	Open the Process Editor and ensure the Task has a valid type configured (e.g., a Module assignment).
8014	NoOutgoingConnections	Error	A Task has no outgoing connections and is not an End Event.	Open the Process Editor and either connect the Task to the next element or replace it with an End Event.
8015	InvalidExecutionState	Error	The execution state is corrupted (e.g., TaskId became null mid-execution).	This indicates an internal consistency error. Re-deploy the Process and retry. If the issue persists, contact support.
8016	ConnectionNotFound	Error	A Task references an outgoing connection ID that does not exist in the Process.	The Process definition may be corrupted. Re-deploy from the Process Editor or revert to a previous version from Process History.
8017	TargetTaskNotFound	Error	A Sequence Flow references a target Task that does not exist in the Process.	The Process definition may be corrupted. Re-deploy from the Process Editor or revert to a previous version from Process History.
8018	LinkTargetNotFound	Error	A link throw event jumps to a link name that no link catch event has.	Open the Process Editor, select the link throw event and pick an existing link name, or add a link catch event with that name.
8019	LinkTargetAmbiguous	Error	Several link catch events share the link name a link throw event jumps to.	Give each link catch event its own link name, then re-deploy.
8020	CallTargetNotFound	Error	A Call Activity has no process to call, or names a process or environment that is not in this workspace.	Open the Call Activity's settings and pick the process (and environment) to call. With Match by environment name, the called process needs an environment named like the caller's.
8021	CallTargetNotDeployed	Error	The environment a Call Activity runs is inactive or has no deployed version.	Deploy the called process to that environment, or activate it.
8022	CallDepthExceeded	Error	Call Activities are nested more than 5 deep, or a process calls itself (directly or through another).	Remove the loop between the processes; repeat steps with a gateway inside one process instead.
8023	StartNotAllowed	Error	This process starts only on its schedule: it has timer start events only, so a chat, form or call can't start it.	Add a Start Event for the Channel that should start it (the StartTask for the chat), beside the timer starts.
8024	StartAmbiguous	Error	Several start events of the process serve the run's channel; keep one start per channel.	Open the Process Editor and keep one Start Event per Channel: remove or replace the extra start, and connect the remaining one to the steps the starts shared.
8025	StartWrongChannel	Error	A channel's start event ran on another channel (e.g. a call start on a WhatsApp run); add a start for that channel.	Add a Start Event for the Channel named in the log (its Module's start), connected to the same first step.
8026	StartInputMissing	Error	A required input of the start step has no value: the run sent none and the input has no default. On the chat it is a warning.	Send the value with the run (a schedule's data, the API payload), or give the input a default in the start step.
8027	StartInputInvalid	Error	A value sent to the start step, or its default, doesn't fit the input's type (a number, yes / no, a date yyyy-mm-dd, a month yyyy-mm) or is not one of its choices.	Fix the value the schedule or API call sends, or the input's type, choices or default.

Plan Limits (9xxx)

Errors raised when a workflow reaches a limit of your Workspace's Service Plan.

Code	Name	Severity	Description	Resolution
9001	PlanExecutionLimitReached	Warning	Your Workspace has used all executions included in your Service Plan for the current billing period.	Review your usage on the Dashboard. Upgrade your Service Plan, or wait for the next billing period.
9002	PlanConcurrentExecutionLimitReached	Warning	Too many Sessions were running at the same time for your Service Plan.	Wait for running Sessions to complete and retry. If this happens regularly, review your usage on the Dashboard and upgrade your Service Plan.
9003	PlanTaskPerExecutionLimitReached	Warning	A single Session executed more Tasks than your Service Plan allows.	Review the Process for loops or unnecessarily long branches. If the workflow legitimately needs more Tasks, upgrade your Service Plan.
9004	PlanExecutionTimeout	Warning	The Session ran longer than the maximum duration allowed by your Service Plan.	Review the Process for long-running branches or waits. If the workflow legitimately needs more time, upgrade your Service Plan.
9005	PlanRateLimitExceeded	Warning	Requests arrived faster than the rate limit of your Service Plan allows.	Retry shortly. If this happens regularly, review your usage on the Dashboard and upgrade your Service Plan.
9006	PlanPayloadSizeExceeded	Warning	A data payload was larger than the maximum size allowed by your Service Plan.	Reduce the amount of data sent to or produced by the workflow, or upgrade your Service Plan for a higher limit.
9007	PlanStorageLimitReached	Warning	Your Workspace has reached the storage limit of your Service Plan.	Review your storage usage on the Dashboard and remove data you no longer need, or upgrade your Service Plan.
9008	PlanEnforcementUnavailable	Error	The platform was temporarily unable to verify your Service Plan limits.	Retry shortly. If the issue persists, contact support.

Audit / Storage (10xxx)

Errors related to storing execution history.

Code	Name	Severity	Description	Resolution
10001	BlobUploadFailed	Error	Part of the execution history for a Session could not be stored.	This is a platform-side issue. Retry; if it persists, contact support.
10002	AuditSerializationFailed	Warning	The detailed step data for part of a Session's execution history could not be stored. The Session itself continued, and its state and logs were saved.	This is a platform-side issue. Retry; if it persists, contact support.

How error codes work​

Generic (0xxx)​

Other (1xxx)​

Flow (2xxx)​

Task (3xxx)​

Module (4xxx)​

Token (5xxx)​

Process (6xxx)​

Session (7xxx)​

Environment (8xxx)​

Plan Limits (9xxx)​

Audit / Storage (10xxx)​