Insufficient stock qty for group transfer or reversal of WBS:&1 by &2

What causes this issue?

The system did not find enough stock in the <AB>PMMO_STOCK</> table or
<AB>PMMO_TRANSIT </>table. This may be due to the following:
Program error
Stock situation was incorrect in the <AB>PMMO_STOCK </>table
Stock situation was incorrect in the <AB>PMMO_TRANSIT</> table

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

System Response

The material document cannot be posted.

How to fix this error?

If the material is batch relevant, make sure the correct batch number is
entered.
If everything is correct, contact your system administrator.

Procedure for System Administrators

Error message extract from SAP system. Copyright SAP SE.