Certificate error and no GUI
Getting this after 2.5.0 upgrade
How to workaorund that??
That means your browser has an existing copy of the current certificate in its trust store, but the serial was reused. That can happen when renewing a certificate.
You can make a fresh GUI cert by going to the shell and running
pfSsh.php playback generateguicert
Alternately, since that seems to only affect Firefox and related browsers, you can try Chrome to get into the GUI and fix the cert there.
I created a bug report for the case mentioned above when renewing in the GUI: https://redmine.pfsense.org/issues/11514