Firefox: using a link to get to Cockpit login page results in 401 Auth failed

Explain what happens

AlmaLinux 9.1, Cockpit 276.1-1, Firefox 107

Using the homelab dashboard "Dashy". When I click a link in Dashy, a new Firefox tab is opened to the target destination of the Cockpit system. I'm going from my domain (reverse proxy) to the IPv4 of the Cockpit system (but IP to IP exhibits same issue).

Attempting to login to Cockpit this way produces the issue where the credentials aren't declined (on screen, like if you enter an incorrect password), but the login page just reloads. Firefox reports "Cookie “cockpit” with the “SameSite” attribute value “Lax” or “Strict” was omitted because of a cross-site redirect." But there doesn't appear to be any redirect happening with Dashy.

This setup works on Edge/Chromium (can follow dashboard link to Cockpit) with no changes. This setup works with every other web services I'm hosting.

This does not appear to be a Dashy problem, as it works with every other web service I'm using, and works with Cockpit if using Edge/Chromium. This does not appear to be a Firefox problem, as it works with every other web service I'm using. Additionally, if I copy/paste the Cockpit address in the address bar, I am able to login normally.

I'm not sure what the problem is, hoping somebody here will be able to point me in the right direction.

Only Cockpit seems to be struggling here, and I can't find any information on this issue. I've attempted implementing sections from https://cockpit-project.org/guide/latest/cockpit.conf.5, but that hasn't helped. Couldn't find any errors in the Cockpit logs (journalctl -u cockpit)

Version of Cockpit

276.1

Where is the problem in Cockpit?

No response

Server operating system

Red Hat Enterprise Linux

Server operating system version

9.1

What browsers are you using?

Firefox, Edge

System log

No response