Spool number that is assigned to each output request

What causes this issue?

Every output request is assigned a unique spool number. This spool
number is an element of the number range SPO_NUM; due to the limited
number of places, there is only a finite amount of these numbers.

System Response

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

How to fix this error?

Procedure for System Administrators

Error message extract from SAP system. Copyright SAP SE.