It sounds like you have AAA in your configuration. If the switch has connectivity to your AAA server, check the config and the AAA server config. If it does not have connectivity, you'll have to wait for the AAA timeout before it allows local authorization (assuming that is also configured correctly). If not, you'll need to add local authorization after AAA fails.
We have configured the outside and inside Interface with official ipv6 adresses, set a default route on outside Interface to our router, we also have definied a rule , which also gets hits, to permit tcp from inside Interface to any6.
In Syslog I also se...