Desired change to payment scheme category is not possible (table TE638)

What causes this issue?

You want to change the category of a payment scheme. However, the change
you want to make cannot be executed. A possible reason for this can be
that the original payment has been classified as 'not modifiable' (field
<ZH>No PSCatCh</> is selected), or that lines cannot be generated for
the original payment scheme category in online mode (field
<ZH>NoReq.Onl.</> is selected) but they can be generated
for the new category.

System Response

Processing is terminated.

How to fix this error?

Select a valid payment scheme category.

Procedure for System Administrators

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

Error message extract from SAP system. Copyright SAP SE.