Our apps are getting error 500 on this call :
https://www.facebook.com/dialog/oauth?client_id=89dc1edc0036d868930ccbac657e8b7f&redirect_uri=https%3A%2F%2Fapps.fa
Depending on what oauth tool you're using, it's possible to get an error 500 if the API key and/or secret are missing