i suggest to change the mod ReAuth to OAuth, they both fix the invalid session issue by relogin but the latter works with microsoft accounts too. i used it in most of the modpack i played and i had to add it to this pack as well.

Given that Microsoft is forcing everyone to switch over their accounts soon, we probably should use something that works with that.

bumping this since it seems to have been fixed in the latest version
Sintinium/oauth#27 (comment)

Cool, hadn't seen that yet. Thanks for letting us know.

Looking into this, it seems that there's an issue with MS account logins in the current version for 1.12.2 (see Sintinium/oauth#27). Probably will want to hold off until that is fixed.