The newest updates for LibreWolf just implemented stricter/more secure DNS settings by default. You may want to check those to see if that's the issue.
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I have not updated Librewolf since last time it worked (yesterday), but I'll poke around in the settings to see.
Maybe try it out on standard Firefox as a quick test? While annoying, this would help validate that the issue is with the librewolf changes to standard Firefox.
Also note that I also use both proton mail and drive from librewolf. Even today. If it’s a general issue with this setup, it hasn’t hit my machine (yet)
Yes, I've checked this, and it works in regular Firefox.