The event has not yet been delivered

What causes this issue?

You wanted to display the work item for the event, but the event has
not yet been delivered. There can therefore be no receiver.

System Response

The function was aborted.

How to fix this error?

Repeat the function as soon as the event is delivered.

Procedure for System Administrators

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

Error message extract from SAP system. Copyright SAP SE.