Error 42:0:9001:3927 Please, fix it.
This is most likely a problem on your side. Either you have a software that is blocking the game (antivirus, firewall), or your router needs to be set up correctly, allowing the necessary ports. Check this out:
In addition, Guild Wars 2 requires TCP ports 80, 443, 6112 and port 6600 be fully unrestricted and accessible, both inbound and outbound. For further information about opening ports or port forwarding, you can visit the following website: http://www.portforward.com Please note, this site is not affiliated with or supported by NCsoft or ArenaNet.
I’ve been able to play the game since the pre-release date and after about a week of playing a new build was put in place and I started getting this error. Now I can only log in about 10-20% of the time. It’s very interesting that all I kept hearing throughout the resolve of the ticket that I submitted that it was something on my end, but no one could explain how I was able to play the game just fine beforehand. This issue needs to be resolved on Arenanet’s end because most of the people experiencing it are just like myself in that they could play just fine until a new build was introduced. If anything an intelligible response from someone that has any kind of information regarding this issue would be a godsend to myself. Surely someone at Arenanet must be working to resolve this issue on their end.