nginx reverse proxy: ERR_TOO_MANY_REDIRECTS but second site is working - nginx

Question

i'm relatively new to linux. My server is running Ubuntu 22.04 and i got a little problem here in my nginx configuration. I set up a reverse proxy (nginx) in /etc/nginx/sites-enabled/reverse-proxy.conf and wrote this into the file:
server {
if ($host = domain.de) {
return 301 https://$host$request_uri;
}
listen 80;
server_name domain.de;
return 404;
}
server {
server_name domain.de;
listen 443 ssl http2;
listen [::]:443 ssl http2;
ssl_certificate /etc/letsencrypt/live/domain.de/fullchain.pem;
ssl_certificate_key /etc/letsencrypt/live/domain.de/privkey.pem;
include /etc/letsencrypt/options-ssl-nginx.conf;
ssl_dhparam /etc/letsencrypt/ssl-dhparams.pem;
proxy_buffering off;
server_tokens off;
location ^~ /swagger {
return 404;
}
location / {
root /var/www/html/domain.de;
try_files $uri $uri/ /index-one.html ;
proxy_pass http://127.0.1.1;
proxy_set_header Host $host;
proxy_set_header X-Real-IP $remote_addr;
proxy_set_header X-Forwarded-For $proxy_add_x_forwarded_for;
proxy_hide_header X-Powered-By;
proxy_set_header Range $http_range;
proxy_set_header If-Range $http_if_range;
# proxy_set_header X-Real-IP $http_CF_Connecting_IP;
add_header 'Referrer-Policy' 'origin-when-cross-origin';
add_header Strict-Transport-Security "max-age=15552000; preload" always;
add_header X-Frame-Options "SAMEORIGIN" always;
add_header X-Content-Type-Options "nosniff" always;
add_header X-XSS-Protection "1; mode=block" always;
proxy_http_version 1.1;
proxy_set_header Upgrade $http_upgrade;
proxy_set_header Connection $http_connection;
}
}
server {
if ($host = second.domain.de) {
return 301 https://$host$request_uri;
}
listen 80;
server_name second.domain.de;
return 404;
}
server {
server_name second.domain.de;
listen 443 ssl http2;
listen [::]:443 ssl http2;
ssl_certificate /etc/letsencrypt/live/second.domain.de/fullchain.pem;
ssl_certificate_key /etc/letsencrypt/live/second.domain.de/privkey.pem;
include /etc/letsencrypt/options-ssl-nginx.conf;
ssl_dhparam /etc/letsencrypt/ssl-dhparams.pem;
proxy_buffering off;
server_tokens off;
location ^~ /swagger {
return 404;
}
location / {
proxy_pass http://192.168.198.40:8096;
proxy_set_header Host $host;
proxy_set_header X-Real-IP $remote_addr;
proxy_set_header X-Forwarded-For $proxy_add_x_forwarded_for;
proxy_hide_header X-Powered-By;
proxy_set_header Range $http_range;
proxy_set_header If-Range $http_if_range;
# proxy_set_header X-Real-IP $http_CF_Connecting_IP;
add_header 'Referrer-Policy' 'origin-when-cross-origin';
add_header Strict-Transport-Security "max-age=15552000; preload" always;
add_header X-Frame-Options "SAMEORIGIN" always;
add_header X-Content-Type-Options "nosniff" always;
add_header X-XSS-Protection "1; mode=block" always;
proxy_http_version 1.1;
proxy_set_header Upgrade $http_upgrade;
proxy_set_header Connection $http_connection;
}
}
The second domain is a streaming service called emby and it works, the first domain is a website i want to host and it is based in /var/www/html/domain.de. The directive /var/www/html/domain.de is owned by www-data.
This config gives me an ERR_TOO_MANY_REDIRECTS on domain.de but the second.domain.de is working fine. Why? What am i doing wrong here?
When i change the ip address in the first domain from 127.0.2.1 to 192.168.198.40 the same error occurs. When i add a port to the address like 127.0.2.1:8080; or 192.168.198.40:8080; i get a 502 Bad Gateway error message.
The second domain is working fine in all constellations but i can't get the first domain to work and i don't know how to fix this.
I hope anybody can help me out here. :)