SAP Message N4600 - External number assignment is not supported for provisional appointments

Diagnosis
Sequential numbers for provisional appointments are assigned via thenumber range object ISH_NAPP by means of an internal number range. Inyour system, however, an external number range has been defined forthis number range object. This is not permitted.
Number assignment for provisional appointments cannot be carried out.

Procedure
Please define an internal number range for the ISH_NAPP number rangeobject. Please use the corresponding number range object in client'000' as a reference.