When you setup a server for replication you may find unexpectedly that SQL complains about your server name. The most likely reason is that the SQL Server name doesn’t match your machine name.
Run the following command to take a look:
SELECT @@SERVERNAME, SERVERPROPERTY(‘ServerName’)

The results should be identical. If they are different, you will need to rename your SQL Server name to match the machine name. To do this use the following:

use master
go
-- Remove old Server Name
exec sp_dropserver ‘OLDNAME’
GO
-- Add New Server Name
exec sp_addserver ‘NEWNAME’,’LOCAL’

You then need to restart SQL Server. Now open a new query and run the following again:
SELECT @@SERVERNAME, SERVERPROPERTY(‘ServerName’)
They should now be the same.