When someone change the windows box name or drop the server*
select * from sys.servers
*Require service restart to get effect
the output of @@SERVERNAME & SERVERPROPERTY(‘servername’) should be same, if they are not same you replication will not work, as replication takes physical server name to communicate.
This will also directly affect the application or system which are using your physical server, so always remember when you are changing the physical box make sure to check @@SERVERNAME & SERVERPROPERTY(‘servername’)
To resolve the issue drop the server and add the new name with given host name.