This worked for me:
https://en-forum.guildwars2.com/topic/66275-cant-download-guildwars-game/?do=findComment&comment=1127563
As he said:
1. open cmd -> paste: "nslookup origincdn.101.arenanetworks.com 8.8.8.8" -> take one of the upcoming ips: "Adresses: xxx.xxx.xxx.xxx"
2. go to your host file: "C:\Windows\System32\drivers\etc\" open hosts file (edit as admin)
paste in: "xxx.xxx.xxx.xxx assetcdn.101.arenanetworks.com" at the end of your host file, save it and it should work.
(replace xxx.xxx.xxx.xxx with one of the adresses from the cmd lookup you did before)
@Healix.5819 thanks dude! <3