Time limit exceeded

What causes this issue?

A search query to the directory cannot be fully processed by it, since
it exceeded the upper limit for the processing time set in the
directory.
If this message occurs for the user master synchronization using report
RSLDAPSYNC_USER, there is a situation in which the attribute that
contains the SAP user name is not indexed in the directory.

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.