Interface table CATSMM cannot be locked

What causes this issue?

Once the system has begun transferring time sheet records to MM-SRV,
the interface table CATSMM is locked for other users.
The interface table CATSMM is currently locked. You cannot transfer
data to MM-SRV. It is possible that another user is locking the
interface table CATSMM at present while transferring data to MM-SRV.

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?

Start the transfer again late.

Procedure for System Administrators

Error message extract from SAP system. Copyright SAP SE.