HTTP 400 error on reverse prxy

Hello all,

I get an 400 error when i try to forward ssl traffic from my subdomain to my docker container on the same machine.

My conf file in nginx:


server {
large_client_header_buffers 4 64k;
if ($host = sub.domain.com) {
return 301 https://$host$request_uri;
} # managed by Certbot


error_log /var/log/nginx/logging/80.log debug;
listen 80;
listen [::]:80;
server_name sub.domain.com;
return 301 https://$host$request_uri;


}

server {
keepalive_timeout 60;
error_log /var/log/nginx/logging/443.log debug;
listen 443 ssl;
listen [::]:443 ssl;
server_name sub.domain.com;
ssl_certificate /etc/letsencrypt/live/sub.domain.com/fullchain.pem; # managed by Certbot
ssl_certificate_key /etc/letsencrypt/live/sub.domain.com/privkey.pem; # managed by Certbot
include /etc/letsencrypt/options-ssl-nginx.conf;
ssl_dhparam /etc/letsencrypt/ssl-dhparams.pem;
ssl_session_cache shared:TLSSSL:16m;


location / {
proxy_pass http://172.17.0.2:8080;
proxy_set_header Host $http_host;
proxy_set_header X-Real-IP $remote_addr;
proxy_set_header X-Forwarded-For $proxy_add_x_forwarded_for;
proxy_set_header X-Forwarded-Proto "https";
proxy_read_timeout 90;

}

}

The sub.domain.com is forwaded with an a-record to the server of my public ubuntu server.
When i try sub.domain.com it shows a valid certificate, but with the 400 server error.

There are no errors in my Nginx error log.
In the 443.log i can see the error for the 400 status:

2024/01/04 10:46:50 [debug] 339772#339772: *3350 http proxy status 400 "400 Bad Request"
2024/01/04 10:46:50 [debug] 339772#339772: *3350 http proxy header: "Date: Thu, 04 Jan 2024 10:46:50 GMT"
2024/01/04 10:46:50 [debug] 339772#339772: *3350 http proxy header: "Connection: close"

When i curl to http://172.17.0.2:8080 i get a valid reponse. Firewall is completly disabled.

Hoping somebody can point me to the right direction for fixing this.

Thanks in advance.