Keep losing connection since last patch
Double check your antivirus/firewall softwares, maybe even temporarily disable them and test. Also, check your modem/router, sometimes they have firewalls enabled by default.
https://en.support.guildwars2.com/app/answers/detail/a_id/8994/~error-codes
This tells you the ports that need to be opened for gw2 to function properly.