For whatever reason, you have an IPv6 address other than the link-local address, but it doesn't have a route to where that server is (most likely because it doesn't have a default route).
IPv6 addresses can become configured a number of different ways. For instance, you might be running a teredo daemon (eg. miredo), you may have set up a script that sets an IPv6 address somewhere else, or you might have something announcing routes on one of the network segments this computer is attached to. Either way, use
ip -6 addr to determine which interface it is that has this address, and use that to infer where it is coming from.
Either fix your IPv6 routing, or disable it entirely. How to fix it depends very much on what the specific problem is; in any case, the configuration is very strange (teredo configurations should basically never experience this problem, nor should RA-configured addresses). You can prevent the host from loading an IPv6 stack by blacklisting the
ipv6 module, though really everyone should try to support dual-stack.
This would make the reasoning behind the error more clear; as you've mentioned in your answer it is also possible that both ipv4 and ipv6 have failed.
It's also possible that you are using ipv6 through a tunnel, and your IPv4 routing is broken.