Hello,
I would like to know what message it is giving you when you cannot open the hotmail account. If it says timeout then it is related to the connection, it might be limited or you do not have any connectivity.
If you are having some problems with Hotmail only, then you might have set the restrictions a little bit too high on the firewall settings. You might try to reduce it and see if it works.
You ca also try to see if this is not listed within the restricted website's list on your website options.