Another user mentioned that they’ve temporarily switched to Opera until Google fixes the issue with the Allow Insecure (mixed content) setting not working in the latest version.
I’m hesitant with that approach as Opera is based on the Chromium project now too, so at some point they’ll likely update their underlying engine as well, but it could be an option in the meantime (especially if you disable auto updates).
It’s not clear what the issue is. Since I don’t have other reports of this, I am suspicious that it could be something specific to your account, but there aren’t specific clues pointing to a particular issue.
You would be looking at the console tab. If there were any error messages, they would usually be shown in red. It’s possible that it’s not an application error per-se though and something else is going on with Firefox that’s causing these issues with your account.