What happened to my shared applications???

What happened to my shared applications???

For some reason, I'm the only one able to access my shared applications now. Every other user that I've given access to just gets a screen asking them to create a new application. What happened??? I try to send invites to everyone and people are starting to get in again, but they can't just login directly anymore. Plus most of the additional tabs that I've setup no longer work -- HELP!
derek