No telephony server is assigned to work center &1

What causes this issue?

To start the call, a telephony server must be accessed. The telephony
server must be assigned to the work center where the call is to be
started from.

System Response

The function terminates, the call cannot be initiated.

How to fix this error?

Check whether a telephony server is entered in the settings for your
work center.

Error message extract from SAP system. Copyright SAP SE.