Task processing cancelled due to &1; data is incomplete

What causes this issue?

Parallel processing has been terminated. Your data is incomplete.

System Response

The system issues an error message and will not allow you to continue with this transaction until the error is resolved.

How to fix this error?

Check your server group, particularly the load at the time of parallel
processing. Start the evaluation anew, if necessary, without parallel
processing.

Error message extract from SAP system. Copyright SAP SE.