Can't PING domains with ipv6 address
Solution 1:
I can ping 2001:4802:7805:103:be76:4eff:fe20:2ccd from my side but cannot 2001:4802:7806:102:be76:4eff:fe20:12b6. And the latter address apparently is used as source address on the outgoing connections (as indicated by traceroute).
There is something wrong with this setup.
You can try to remove the problematic address from your configuration and check if this helps:
ip -6 addr del 2001:4802:7806:102:be76:4eff:fe20:12b6 dev eth0
or something similar, I don't remember from the top of my head.