It is difficult to know what the problem is from this debug. Perhaps if it ran a bit longer we might see more of the attempt to negotiate and might see the problem.
But I would suggest that symptoms like this frequently are the result of a mismatch in configuration between the peers. I would suggest that you check to make sure that the peer addresses do match. Also check to be sure that the pre shared keys used for ISAKMP negotiation match.
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...