Table TOADV (mo DMS document type found for &)

What causes this issue?

A DMS document class for &v1& could not be found in table TOADV.

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?

Please maintain table TOADV.

Error message extract from SAP system. Copyright SAP SE.