When I open emails many times the letters are gibberish. The letters are changed into symbols and weird looking letters. Sometimes closing Firefox and reopening helps, but usually I have to restart my computer. Even then, it may or may not be readable. Some emails are only partially this way, but most are complete gibberish. Has been happening for a few months. I have updated Firefox and am running the newest update. I am using Microsoft 365 email. Other computers in the same office do not have this issue. Any ideas how to fix this?