Access to admin url not possible

Hi guys,
I just set up a vServer and installed Strapi with the yarn commands.
I also setup a virtual host to use a subdomain to access the cms.
When I want to access the admin site it is not possible becaus the site loads ages and the is not reachable.
I tried this urls:

subdomain.domain .de:1337/admin
subdomain.domain .de:1337/var/www/cms/admin
subdomain.domain .de/var/www/cms/admin
subdomain.domain .de/admin

Does anybody know why I can not get access to the site?

Thx guys!

Can you provide your proxy config and your server.js with the urls?