Transaction type group & (From transaction type &) not defined

What causes this issue?

The transaction type group is not or no longer defined in your System.
There is probably an error in table maintenance.

System Response

This asset will not be processed with this transaction type. Processing
will be continued with the next asset number.

How to fix this error?

Analyse and remove the cause of the error.

Error message extract from SAP system. Copyright SAP SE.