Unsupported Browser? Safari?

My 2012 Mac Pro is OS blocked at Mojave (10.14.6) and until this morning, Safari ((14.1.2 (14611.3.10.1.7)), has been fine with TMF, but now I’m getting a message:

" Unfortunately, your browser is unsupported. Please switch to a supported browser to view rich content, log in and reply."

What’s up with this? While I have Firefox, Safari has alsos been solid, working… And is my default…

weco