So I encountered an issue where I couldn’t log in to the WebUI after installing MineOS on Ubuntu 22.04, and I came here and found several people having the same issue. I don’t think I saw anyone specifically with Ubuntu 22.04, but the issue I believe will be common among most modern Linux distros. As several posts have pointed out, the issue is the hashing algorithm used for the user you are trying to log in with. The distro uses something other than SHA512 which is what MineOS is expecting.
Reason for posting this is I never saw anyone post a simple solution and I seem to have found one. Assuming you created a new user to login with (you should, don’t just use the default or root!), then you should be able to resolve the issue by the following command (run as root):
echo '<user>:<password>' | chpasswd --crypt-method SHA512
Replacing with the user you created (adduser <user>) and with the password you supplied when creating the user (or a new one, I believe). Now try logging in with the username and password used in the command and it should work!