Do you use the program Web Companion from Lavasoft?

Recent thread identifying that program as a second known "man in the middle" that causes this problem with FB and YT: Facebook and YouTube show up as black diamonds with question marks, and odd numbers and symbols when chosen?

I'll have to look and see if I have that (not familiar with that program at all). Something I forgot to mention is that Facebook started doing this month's ago, YouTube and Amazon (plus any others I haven't discovered yet) have only started doing this recently.

Nothing from Web Companion on my computer. This is a continuing issue which, funny enough, now does the same thing on the Zenmate page. I was able to see any website when logged into Zenmate and now can't even log into it! I have tried changing things back to "default" in the "About:change" Mozilla page, still no luck. Uninstalled and re-installed Zenmate, no dice. I'm running Windows 10 and it seems like this issue is getting worse and it is ONLY happening in Firefox. May need to ixne Firefox as a browser which I really don't want to do :/

Do you have a problem with gibberish characters replacing normal characters within the website's expected layout -- potential font corruption issue -- or do you get a full page of black on white gibberish characters as in the earlier-linked thread?

eska said

I was able to see any website when logged into Zenmate and now can't even log into it!

How does Zenmate work with browsers? Is there an extension or plugin that it requires, or does it modify your connection at the system level? Please check with Zenmate on whether it works in Firefox 52+ (only plugin allowed is Flash) or requires the Extended Support Release (ESR) version of Firefox 52, which allows all the plugins allowed in Firefox 51.