This page:
https://support.mozilla.org/en-US/questions/131588...gives possible reasons for it
o DNS over HTTPS - if you use that with Firefox, maybe it can break I guess.
This is a nice thing to do for extra privacy with DNS look ups. I use this myself (mostly on a chromebook) and haven't had an issue. It sounds like Firefox may have an issue with it. If you turned this on, you can try turning it off, I guess.
o "Firefox wasn't able to find a cipher suites to use to connect to this server "
I have some understanding of this sort of thing. This is technical. My server when it does https connections (which is most of the time these days), it has to negotiate how to make a secure connection with your web browser. Part of that is determining which cipher to use. There are many, some are weak (obsolete/insecure).
I recently did some work on my web server to be the best it can be security-wise for SSL.
e.g.
https://www.ssllabs.com/ssltest/analyze.html?d=gam... A+!
Part of this is to not allow the weak ciphers and use only recent TLS protocols.
On the other side of this, you can test your web browser but loading this page:
https://clienttest.ssllabs.com:8443/ssltest/viewMy...Both pages mention ciphers. So, I assume it's somewhat related to the Firefox issue (if it's cipher negotiation related). Though, I don't see how it would work sometimes and not others.
Mostly, I don't really know what the deal is here. I don't think it's something I can fix on my end based on what I've read.