Hotmail is rolling out a server change at their end which might be causing this problem. Mozilla has spoken to them about it and they are trying to fix it. I won't be able to provide a time estimate by when it will be solved but hotmail/mozilla is certainly looking at this issue.

I will let you know if get any updates!

I've posted an update on https://support.mozilla.com/en-US/questions/835441

Thanks for the reports and for using Hotmail.

Raul.

I found an answer on here about disabling the foxit plugin and it worked! I've been using Chrome to access Hotmail because it doesn't have any problems but my hotmail functionality has returned since I disabled the plugin. Whoever posted the answer a big THANKS!