Had this issue today. For some reason, both my accounts (including root) were set to expire March 1, 2023. Was not able to log into the Web Gui. Was, however, able to log in to the CLI via SSH. Couldn't find a fix anywhere and finally figured it out.
When I did a user list, it showed both my accounts with the expire set at 1677657600 which is the epoch for Mar 1, 2023. Used the following command to reset expire back to never:
pveum user modify root@pam --expire 0
When I did a user list, it showed both my accounts with the expire set at 1677657600 which is the epoch for Mar 1, 2023. Used the following command to reset expire back to never:
pveum user modify root@pam --expire 0