It is possible that the hotel is blocking access to that particular chat program, as well as all other programs that use the same software. (I hope I am using the terminology right)
I do know that where I work, we have wireless access, but there are certain programs like chat, that we cannot use. I can access other chat programs, that use different software . I double checked the error message and it is the same as what you are recieving now.
The programs are blocked for a reason, but I never bothered to ask.
Even if you try to disable or change your firewall it will still not work.