Sounds to me as if your browsers are trying to block mixed content. If so, the solution I'm currently familiar with is not too elegant.
A Firefox solution: (For other browsers, apply trivial generalization.)
Notice the shield icon next to the location bar.
Click it and instead of the option "Keep Blocking", choose "Disable Protection on This Page". This should fix the problem until you refresh the page, which is pretty lousy.
For a permanent solution, you can go to Firefox's "about:config", and change the boolean value of security.mixed_content.block_active_content to 'true'. I also find this solution lousy, as it is a potential security concern.
As to why this problem so suddenly loomed, I myself am perturbed.