Shopware5 with a reverse proxy forwarding issue - docker

Question

I have installed shopware5 in a docker container and made it to go out with a reverse proxy nginx.
After the installation, the main page of the website works, but when I click on any of it's tabs, it forwards to the container directly and changes the address in the URL to the address and the port of the container. Therefore it shows that the website cant be reached.
I am wondering if this could be something related to the nginx or the shopware itself.
Any advises will be greatly appreciated.
this is the configuration of the proxy:
server {
listen 443 ssl http2;
# listen 80 http2;
server_name domainname.com;
ssl_certificate /etc/nginx/certificates/domainname.crt;
ssl_certificate_key /etc/nginx/certificates/domainname.key;
ssl_session_timeout 10m;
ssl_protocols TLSv1 TLSv1.2;
ssl_prefer_server_ciphers on;
ssl_ciphers ECDH+AESGCM:DH+AESGCM:ECDH+AES256:DH+AES256:ECDH+AES128:DH+AES:ECDH+3DES:DH+3DES:RSA+AESGCM:RSA+AES:RSA+3DES:!aNULL:!MD5:!DSS;
ssl_ecdh_curve secp384r1;
# root /var/www/html;
error_log /var/log/nginx/domain-error.log;
access_log /var/log/nginx/domain-access.log;
add_header Access-Control-Allow-Origin *;
location / {
proxy_pass http://localhost:8081/;
}
}