You cannot edit table group &

What causes this issue?

You want to change, display or delete table group &V1&. You cannot do
so because either the table group was not created using this tool or
subsequent manual changes were made to the table group in the
ABAP/4 Dictionary.

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?

Check the table group beforehand.

Error message extract from SAP system. Copyright SAP SE.