Getting 'Error 431: Request Header Fields Too Large' – How Do I Fix This? or What Causes Error 431 an

OP here—y’all are legends! Tried the VPN tip and... it worked?! Turns out my VPN was adding a novel’s worth of headers.

Still weird it only happened on some sites, but hey, problem solved.

Follow-up Q: Anyone know why some sites care about header size and others don’t? Is it just server config differences?

Thanks for the help! 🙌