Physical object &1 could not be locked

What causes this issue?

An error occurred during use of function module API of the SAP
Knowledge Provider. The physical object &v1& should normally be locked
using function module &v2&. This was not successful.

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?

Procedure for System Administrators

Error message extract from SAP system. Copyright SAP SE.