No user master exists for this user

What causes this issue?

You want to enter the name of the user responsible for a document info
record. However, there is not user master record under that name in the
SAP System.

How to fix this error?

Check the name.
If you still want to enter this user as responsible for the record, a
user master must be created in the SAP System first.
To do this, contact your system manager.

Error message extract from SAP system. Copyright SAP SE.