Try to install this extension and turn it on for chrome-only websites: Chrome mask

I installed Chrome Mask as suggested, then turned it one, went to www.pge.com/, clicked the Sign In button, which took me to https://m.pge.com/, accepted strictly necessary cookies, and then a blank screen. With Edge and Chrome, the next page is the actual sign-in screen. I verified the Chrome Mask was one, but evidently it is not working as expected. Running Firebox 129.0.2 on Windows 10 64-bit host.

You can check the Web Console for relevant-looking messages.

• https://firefox-source-docs.mozilla.org/devtools-user/web_console/

The blank screen described above is the symptom with or without Chrome Mask, it seems, I haven't attempted Chrome Mask. I do experience the blank screen.

The PGE site has complained that FireFox is unsupported for at least a year, however, one could log in and pay bills. PGE announced a website update recently and now the blank screen presents rather than the sign in dialog.

This is a big deal right FireFox shouldn't allow itself to be locked out?

Did you check the Web Console Like I posted above?

Did you check for issues with Total Cookie Protection?

• https://support.mozilla.org/en-US/kb/total-cookie-protection-and-website-breakage-faq
• https://support.mozilla.org/en-US/kb/introducing-total-cookie-protection-standard-mode