Issue
Receiving a "service '?' unknown" or "service 'sapmsxxx' Unknown" error message when attempting to connect to a Message Server.
Cause
This issue is often caused by a missing sapmsXXX entry in the \WINDOWS\SYSTEM32\DRIVERS\ETC.\SERVICES file.
Resolution
Edit the file \WINDOWS\SYSTEM32\DRIVERS\ETC.\SERVICES and add the following line to the end of the file updating the PRD and 3600 values as noted below. NOTE: Be sure to click the Enter key after the entry so it looks like the last line is blank.
sapmsPRD 3600/tcp
Update the 2 bolded fields with the following:
PRD: System ID of the Message Server
3600: Port Number