Studio Copy Step Fails with NoMediationMessageContentException Empty Message
What it means
A Copy step in a Workday Studio integration throws NoMediationMessageContentException because the message payload feeding into that step is empty at runtime, even though earlier steps in the assembly appear to complete without error. This usually points to an upstream step producing no output rather than a problem with the Copy step's own configuration.
Troubleshooting
- Add a trace or file-write step immediately before the failing Copy step to confirm exactly what payload, if any, reaches it at runtime.
- Check the step immediately upstream (commonly an HTTP retrieve, CSVtoXML, or a variable-based Input step) for a silent failure, such as an empty response body or a variable that was never populated.
- Verify the Input configuration on the Copy step itself. If Input is set to Variable, confirm the variable name matches exactly where it was set upstream and that Stream XPath settings match the actual message shape.
- Re-run with a static, known-good test payload injected directly before the Copy step to isolate whether the issue is the Copy step or the data feeding it.
Insert a trace or log step directly before the Copy step to confirm whether the message is genuinely empty at that point, then fix the upstream step that is producing it.
Add explicit null or empty-message validation immediately after any step that produces dynamic content, such as an HTTP retrieve, file read, or transform, so a silent empty payload fails fast with a clear message instead of surfacing later as a generic mediation exception deep in the flow.