Login to the main appliance interface may fail after restore. This may happen specifically when restore has been done to another box for migration or test restore purposes. All logins including the default admin account affected.

The usual cause is host checking option described here, https://docs.device42.com/device42-appliance-manager/set-fqdn-for-web-access/. In spite the appliance is initially accessible restore overwrites these settings and login process is affected accordingly.