The following procedure explains how to disable Client Certificate Check from CLI after an interface is no longer accessible due to recent certificate import and/or Client Certificate Check activation via System | Administration on UTM devices.
*Username: 'admin'.
*Password: 'current_password'.
admin@C0EAE45C6ECC> config
config(C0EAE45C6ECC)# administration
(config-administration)# no web-management client-certificate-check
(config-administration)# exit
Now you should be able to access the management interface using the default certificate.