Maybe, but it seems somewhat specific to kbin.earth to me. The error logs blued_gear saw might help the right people understand the issue too and dig in further if there’s something that needs fixing either in mbin or lemmy.
The one other mbin instance using 1.10.1 that federates with grad doesn’t have the same issue with the same users at least:
- tardigram
- gehirneimer.de does not federate
- rimworld.gallery does not federate
- thebrainbin.org does not federate
- fedia.io and kbin.melroy.org both require sign ins