Solved: nginx + internal hostname

[MaDe]

Good day,

I setup a nginx reverse proxy but I have two problems that I cannot resolve.

1. When I request  <sub.example.com> it changed the URL to my internal hostname <hostname/folder1/folder2>.
2. When I request  <sub.example.com/folder1/folder2> it is working but it is planned that only the domain will be
    shown.

And maybe third problem....I am new to nginx.
Can someone point me in the right direction? Many thanks for your help.
Thx MaDe

Solved:
Ok got it.. on the backend server was a redirect to a subfolder configured.