Quoting info at smallinnovations dot nl (info@???):

> I had something similar but with ssh. Some debugging learned that IPv6
> was preferred but my ISP connection does not have IPv6. After 60 seconds
> ssh time out and changed back to IPv4 and made connection after all.
> After this discovery I disabled IPv6 on my local network.

This is a common problem and is why you shouldn't test networking
problems using Web browsers, but rather with simple command-line tools
such as dig, ping, traceroute, and tcptracroute.

I note that dig has flags '-4' and '-6' to limit DNS resolution to only
IPv4 or only IPv6, respectively.