Wrong username or password after upgrade

[G]

Hi,
I've upgraded 2 members of a cluster yesterday.
Backup member upgraded OK, but after upgraded master, I can't login back on ssh or webgui.
Any ideas on how to recover from this?
I've rebooted it several times hoping it will load properly, but I see no error messages.
This is what i get on the syslog:
<11>Aug 26 08:56:50 opnsense: /index.php: Web GUI authentication error for 'USERNAME' from 192.168.1.15

[jjanzz]

I hope you have substituted 'USERNAME' with the actual username?

Do you have physical access to the machine - and if so, is the console menu accessible or did you protect it with a password?

[G]

It's a VM, ssh access is protected  and VT is off.

[G]

As mentioned on another post, solved with the password reset option from the iso.