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This page lists the error messages FlowX.AI users hit most often, with the exact message text so you can find it by search. Each entry explains what the error means, its usual causes, and where to fix it.
Copy the exact error message into the search bar or the AI assistant - the entries below use the platform’s exact wording.

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How FlowX reports errors

Process errors (incidents): when a process instance hits a problem, the error details attached to the instance include a Source (the node or action that failed), a Cause Type (one of the messages below), and a Timestamp. Example of what you’ll see: 
Source: ACTION (set_premium)
Cause Type: Invalid business rule expression.
Type: Business Rule
Timestamp: 2026-06-01T09:07:31.717Z
API errors: REST endpoints return errors in application/problem+json format, with a type of https://www.flowx.ai/error, a human-readable title, and an HTTP status: 
{
  "type": "https://www.flowx.ai/error",
  "title": "Entity not found.",
  "status": 404
}

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Business rules and gateways

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Invalid business rule expression.

The script attached to a business rule action could not be parsed or executed. Common causes:
  • Syntax that is invalid for the selected scripting language - a rule written for one language while the action is set to another.
  • Referencing process data keys that don’t exist yet at the time the rule runs.
  • Language features that the embedded runtime doesn’t support - the rule can pass an editor check but fail at runtime.
Fix: open the business rule on the failing node, confirm the selected language matches the syntax, and test with the data the instance actually has at that point. See Business rule action.

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Could not execute condition.

A condition expression on an action failed to evaluate. Same causes and fixes as invalid business rule expressions - check the expression’s language and the data it references.

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Invalid gateway rule. / The rule returned no result. / Missing sequence from gateway rule evaluation.

An exclusive gateway could not pick an outgoing branch:
  • Invalid gateway rule. - the rule expression itself failed to evaluate.
  • The rule returned no result. - the rule ran, but no branch condition matched the instance data.
  • Missing sequence from gateway rule evaluation. - the rule picked a branch that has no outgoing sequence configured.
Fix: make sure the gateway’s conditions cover every possible data state (add a default branch) and that each branch connects to a next node. See Exclusive gateway.

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Executing a script produced an error!

A Script node inside an integration workflow (not a process business rule) failed - the message is followed by the underlying cause, for example SyntaxError: expected '(' at line 4, column 9. Fix: open the workflow’s Script node and correct the JavaScript or Python code at the reported line. Test the node individually before re-running the workflow. See Integration Designer.

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Timers

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Invalid timer definition. / Timer expression is not valid

The timer event’s expression could not be parsed - typically a malformed cron or ISO 8601 duration expression. Fix: validate the expression format against Timer expressions.

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Timer could not be triggered due to invalid format of process parameter.

The timer is configured with a dynamic value from process data, and at runtime that parameter held a value that isn’t a valid timer expression (wrong format, empty, or not a date/duration). Fix: check the process data key the timer reads and make sure every path that reaches the timer sets it to a valid cron or ISO 8601 value. See Timer events.

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Messages and correlation

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The message does not follow the custom integration data model.

A message received from an external system (or sent to one) doesn’t match the data model configured on the integration. Fix: compare the actual message payload against the data model defined for the integration - field names and structure must match exactly. See Integrations.

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Invalid send message structure. / Invalid receive message structure.

The data mapped on a Send Message Task or Receive Message Task doesn’t match what the node expects - usually a mapping that references missing keys or produces the wrong shape. Fix: review the node’s data mapping against the message structure. See Message events.

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Correlation errors on throw and catch events

  • Correlation value null or empty for throw event. / Correlation key null or empty for throw event. / Event name null or empty for throw event. - the throw event is missing its identification, usually because the process data key used as correlation is empty at runtime.
  • No catch events with event name and correlation value. - the message was thrown, but no waiting catch event matched both the event name and the correlation value.
  • Duplicated correlation value. - more than one waiting catch event matched the same correlation value, so the message can’t be delivered unambiguously.
Fix: make sure the throw and catch events use the same event name, and that the correlation key resolves to a unique, non-empty value on both sides. See Message events.
Token waits forever at a Receive Message Task? That is usually not an error but a correlation miss: the reply arrived with a different event name or correlation value than the catch event expects, or the workflow/subprocess completed without sending it. Check the three correlation errors above first.

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Subprocesses

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Missing subprocess definition or a published version. / The subprocess couldn’t start because we couldn’t find a published version.

The parent process references a subprocess that either doesn’t exist in the project (or its dependencies) or has no published version in the active build. Fix: publish the subprocess and make sure the build that runs includes it. See Subprocess.

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Incorrect action configuration, the subprocess is missing or is not referenced correctly.

The Start Subprocess action (or embedded subprocess node) points at a subprocess name that can’t be resolved - renamed, moved, or not referenced through the right dependency. Fix: re-select the subprocess in the action/node configuration. See Subprocess.

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Could not render subprocess due to multiple swimlanes or missing Parent Process Area.

An embedded subprocess can’t render its UI. The platform requires the embedded subprocess to have exactly one swimlane and to define a Parent Process navigation area that its UI renders into - this error means one of the two is missing. Fix: in the subprocess definition, reduce to a single swimlane and add a Parent Process navigation area for its UI. See Subprocess.

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SubProcess params cannot be parsed.

The data passed to the subprocess at start couldn’t be parsed - usually a mapping that produces malformed or unexpected data. Fix: check the input mapping on the subprocess start configuration.

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API errors

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Entity not found.

A 404 in the standard error envelope: the resource referenced by the request - a file, document, process instance, or other entity - doesn’t exist or isn’t accessible with the caller’s permissions. Frequently seen on file previews and document URLs when the file ID is wrong or the underlying file was deleted. Fix: verify the identifier being requested and that the caller’s role can access it.

Glossary

The FlowX.AI vocabulary - what each core term means.

Cookbooks

Tutorials, guides, and reusable patterns.
Last modified on July 6, 2026