Can't use Teamviewer since I got back to school?

[retrospect1316]

I can't use Teamviewer at all since I got back to my school. Before that, it was running without a problem in my house and in hotel.
Right now when I open Teamviewer, it doesn't show my ID and password, and it keeps popping out a window saying that "Please check your internet connection. Most likely you use a proxy server and you have to enter the proper information in the option dialog."
I have my proxy setting at automatically detect setting. I'm connecting to my dorm's internet, which is a public internet. I have tried connecting both wired and wireless (with a router), but Teamviewer still doesn't work at all.
Please help, I really need to use Teamviewer, thank you.

[Admin]

Often the simplest thing to do is uninstall,  then reinstall teamviewer, often this resolves the issue.