Internal Error 500 at Plinth main start page

*FreedomBox is plugged into router at home
*FreedomBox Pioneer Edition from March or April 2019
*Running Version 19.15, says it’s up to date

Upon going to the URL which usually goes to my FreedomBox from a device that has logged in before, I get an internal error 500. If I instead go to the URL from a device that I have not logged in with before, I can go to the login page, but upon submitting my login info, I get an internal error 500. I tried SSH’ing into my FreedomBox, and it establishes the connection, but upon submitting my login info, I get “access denied” (regardless of what user I try to login with). It kind of seems like there’s been a failure of some kind with the users/groups table? How can I regain the ability to access my FreedomBox?

Thanks!