I installed a new Windows 2012 server with SQL 2014. Logging in via Windows authentication was successful but when I tried to login via the sa account I was given the following error:
A connection was successfully established with the server, but then an error occurred during the login process No process is on the other end of the pipe.
It appears the default installation did not include mixed mode authentication. To fix this issue, log into SQL Server Management Studio using Windows Authentication. Right click the SQL server and select Properties -> Security. Then select SQL Server and Windows Authentication mode.
Next you'll need to enable the 'sa' user. In SQL Server Management -> Security -> Logins -> Right click 'sa' -> select Enabled under Login