Service Unavailable error & TFS Server

When installing TFS server, make sure that the TFS Setup account has never expire password settings or not locked for any reason since if this account's password changed you will receive the above error

So simply reset its password and

1. update the windows services that log on using the account
   
2. Update the password on the application pools where this account used (TFSWSSADMIN , TFS AppPool and TFSWSS)
   
3. Restart these app pools and ping your devs to continue bugging