Can't set up Pixelfed as a cross-posting option

I’m trying to set up the Pixelfed cross-posting (gram.social) but keep getting the error message below:

Error while processing the request. Please try again or email help@micro.blog. Check the news blog for updates

I looked into this error behind the scenes and the Pixelfed server was returning the error: “400 Request Header Or Cookie Too Large”

I’m going to fix Micro.blog to more gracefully handle this error. I don’t think I’ve ever seen that before. Does it still do that if you try again?

Just tried it, and I’m still getting the same error message. Is it possible that gram.social is set to block posting via the API?

These size limits seem… plausibly to blame.