Server appears unresponsive. All others can join.

Hello. Recently a Server that I am an Administrator on went down, and came back up awhile later.

It seems that when I try to find it on the Server list, it is not there, nor in any of the other tabs (History, Favorites etc.)

I have tried every other way to join including but not limited to: Connecting by IP, Connecting through friends, and So forth.

I am the only one having this problem so far, and my friends have no idea what is wrong.

Any thoughts?