MAIL won't load?

[cheddar-caveman]

2018 MBP running Monterey 12.6.8

Yahoo mail won't load? Press the mail icon and just this message or a blank screen?

"upstream connect error or disconnect/reset before headers. reset reason: connection termination"

 

[cheddar-caveman]

Did a Malware scan, all ok, then ran Onyx, cleared everything out, and all back to normal.
No idea what the problem was!