No caller data found for telephone number &1

The data for the caller (name, firm, address) could not be determined
from the telephone number.
The following actions were executed:
The called number was assigned to user &V2&.
The caller was searched for in the data areas assigned to the user,
using the calling number &V1&.
The caller was not found in the data areas.
There are a number of possible causes:
The user called has either not entered data areas in their user settings
or has entered incorrect data areas, that is data areas that are not
suitable for their task area.
The caller does either not exist in the SAP system or in the correct
data areas.
The address of the caller does exist, but there is no telephone number.
The format of the telephone number with which the caller is stored in
the system, does not correspond to the format of the number with which
the call was reported in the system.
You can search for the caller manually in Business Address Services:
Select 'Search for caller'. When you have selected an address, you can
assign the inbound telephone number to this address. This ensures that
the caller data will be determined correctly when the same person calls
again.

Error message extract from SAP system. Copyright SAP SE.