Why can I not use Firefox anymore on my Imac 2015 on Mojave?

You can try signing in using a new Private Window if there's any difference.

In general sites no longer support your version, and there have been both chatGPT and Xitter breakages in the recent months (that they fixed later, possibly after user reports), so if you rely on these services, you might start looking into upgrading your Mac.

Firefox 116.0 and later including the current Fx 157.0 Release and 153.4.0 ESR requires macOS 10.15 (ten.fifteen) or later to run.

https://support.mozilla.org/en-US/kb/firefox-users-macos-1012-1013-1014-moving-to-extended-support

I tried signing in to a private window. It just stopped working. Oh well. I can use Chrome. I prefer Firefox because it saves my frequently used web sites (bank, credit card, chatgpt, etc.) I actually own 3 Imacs, 2 are the 2015 model on Mojave and one 2020 model on latest Sequoia. I have 4 laptops all on different versions of OS for various reasons. I am 74... been on a mac since my first one in 88 and have owned and sold numerous macs. Usually always for good $$ while I bought a newer model. BUT because of certain software I use I prefer Mojave. It doesn't have "issues" constantly like Sequoia that drive me nuts. I can quickly get what I want done in the older versions of Quark Xpress, Adobe Photoshop, Illustrator and Quicken 2007. I also own an Astrology softwear I paid $1800 for back in the day and i still use it to draw up birth charts. No company does the birth wheel as beaufitully as I/O did. :)

Anyway, Chrome is working for chatgpt and x. Ventura on a lap top works for. my Chase bank acct. on Firefox. I will have to live with Chrome's pissing me off by. making me double sign in for everything.

Thanks for your responses.