There is a bug in Firefox which results in:
The site at Lockdown Rules in Scotland has experienced a network protocol violation that cannot be repaired.
The page you are trying to view cannot be shown because an error in the data transmission was detected.
Please contact the website owners to inform them of this problem.
This bug is known and Discourse support can do nothing about it. When it happens apparently it goes away after a few hours.
This normally happens when the SSL certificate has been updated. I saw briefly this morning but Firefox is working fine now.
This was made more complex because my work laptop has been misbehaving and has gone for a good kicking in the IT dept and I have a temp laptop so I’m reinstalling stuff I need. Tedious.
@MM0FMF As you say: …
Frome Discourse Support: happens shortly after a certificate has been automatically renewed, in combination with a LetsEncrypt server