Hey Till, i have configured my domains with 2 A records, for testing purposes i switch off server1 and the websites now show:
Welcome to nginx!
If you see this page, the nginx web server is successfully installed and working. Further configuration is required.
For online documentation and support please refer to nginx.org.
Commercial support is available at nginx.com.
Thank you for using nginx.
Further investigations show that in the folder /etc/nginx/sites-enabled/
on server1 are not the same with server2 do i also have to sync them just as the /var/www/ folder?