Phrase group &2 does not exist in phrase library &1

What causes this issue?

You entered a phrase group which does not exist.

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

System Response

The system has an error status and requires an acceptable phrase group.

How to fix this error?

Enter an acceptable phrase group or delete the incorrect one.

Error message extract from SAP system. Copyright SAP SE.