Diagnosis
You wish to create a service master and have assigned a key for it.

System Response
No external number range has been defined for the service categoryentered.

Procedure
If you wish to assign an external number, invoke the function formaintaining the number ranges for the service master (in Customizing).Determine the group to which the service category you are usingbelongs. Extend the number interval of this group by adding an externalnumber range.