The second key field of table & is not MSID

What causes this issue?

Table &V1& cannot be defined as message destination for one of the
following reasons:
The MSID field is not the second key field of the table.
The domain assigned to the MSID field does not belong to the same data
type as the CO_MSID domain.
The domain assigned to the MSID field does not define the same field
length as the CO_MSID domain.
The destination is not created.

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 definition of table &V1& in the ABAP/4 Dictionary and
correct it according to the requirements listed above.

Error message extract from SAP system. Copyright SAP SE.