I use a Mac. Since version 12 Firefox has not worked well at all. I tried several times to get it to work. Rebooted, updated as much as I knew to update and tried again. Won’t work with AT&T / Yahoo mail since it locks up and won’t upload attachments.
Looked for some solution to problems, others seem to have them as well and have not found a solution either.
Really liked Firefox but it stopped working for some reason.