Well, assuming this will be moved eventually, I'll try to answer your question.
Are you sure the server is still online? I once added a server to my favorites list, and it went down, so I had this ip address with 0/0 players attending, rather than the server I listed.
As for refreshing: does it go away if you quit and reopen JAMP? If so, you don't really have a problem. At least, that's what I do when it happens to me. I just take a break for a while, and when I go back everything is generally back to normal. It may be due to rocky Internet connection, or something. I don't know.
Sorry if that's vague. It's all speculation, mind you. If your problem persists, I'd seek technical support.