Hi   ! Could you be a bit more specific,   like : What do these error messages say   ?

Well when loading a page with an error it says "An error occurred while displaying this deviation" and this happens a lot. As for the error messaging I get this "An error has occurred: DiFi Request Failed". I've done a screenshot of this one since it looks like a really unusual error.

This could be caused by corrupted cookies or cookies that are blocked.

Clear the cache and cookies only from websites that cause problems :

Clear the Cache:

3-bar menu => Options => Advanced => Network => Cached Web Content :
"Clear Now"

Remove Cookies from sites causing problems:

3-bar menu => Options => Privacy => Cookies : "Show Cookies"

If the above doesn't fix it, then let's try Firefox in Safe Mode :

If Firefox is not running : Hold down the Shift key when starting Firefox. If Firefox is running : 3-bar menu => ' ? ' (at the bottom of the dropdown) => 'Restart with Add-ons disabled'. Then OK the restart. A small dialog should appear. Click 'Start in Safe Mode' ( not 'Refresh' !)

See : https://support.mozilla.org/en-US/kb/troubleshoot-firefox-issues-using-safe-mode

And also : https://support.mozilla.org/en-US/kb/troubleshoot-extensions-themes-to-fix-problems?redirectlocale=en-US&redirectslug=Troubleshooting+extensions+and+themes

Thanks, clearing the cookies and cache works. :)

Rocketeer-Raccoon said

Thanks, clearing the cookies and cache works. :)

My pleasure   ! So glad your problem's solved   !