What do you see when you type ping myserver.com
in a command prompt. If you don't see a ping to an 12.34.56.78 like address, but to some '2001:888:0:7::77' style address your server most likely resolves to an ipv6 address before it resolves to an ipv4 address. (Note that localhost
has this problem)
Subversion 1.8 switched to a new http implementation and this implementation currently doesn't try to connect to further addresses resolved by the DNS resolver.
The problem is that many Subversion servers don't listen to ipv6 connections yet, while by using the machine name as a service name you tell your http client (in this case Subversion) that your server does support ipv6.