I have local installation of TFS Express 2013 on my machine. All of a sudden it started giving this error “Service Unavailable 503” when I tried to open Visual Studio Team explorer.
I thought something got corrupted as I was trying to install some other Visual studio updates. So I re-installed TFS but got same error.
After searching online, I cam across this one here.
So indeed my TFS application pool was stopped. I restarted the AppPool but noticed as soon as I try to access my local tfs via webclient it would stop the AppPool again.
That reminded me to look at the EventViewer and I saw the real error that was causing the site to crash. Some how my machine.config got corrupted when I was changing the mailsettings.
After correcting that error, TFS started working.