You can try this, its working for me:
server {
if ($host = gitlab.xxxx.xx) {
return 301 https://$host$request_uri;
} # managed by Certbot
listen 80;
server_name gitlab.xxxx.xx;
return 404; # managed by Certbot
}
server {
server_name gitlab.xxxx.xx;
listen 443 ssl http2; # managed by Certbot
ssl_certificate /etc/letsencrypt/live/gitlab.xxxx.xx/fullchain.pem; # managed by Certbot
ssl_certificate_key /etc/letsencrypt/live/gitlab.xxxx.xx/privkey.pem; # managed by Certbot
include /etc/letsencrypt/options-ssl-nginx.conf; # managed by Certbot
ssl_dhparam /etc/letsencrypt/ssl-dhparams.pem; # managed by Certbot
access_log /var/log/nginx/gitlab_access.log;
error_log /var/log/nginx/gitlab_error.log;
location / {
client_max_body_size 0;
gzip off;
proxy_read_timeout 300;
proxy_connect_timeout 300;
proxy_redirect off;
proxy_http_version 1.1;
proxy_set_header Host $http_host;
proxy_set_header X-Real-IP $remote_addr;
proxy_set_header X-Forwarded-Ssl on;
proxy_set_header X-Forwarded-For $proxy_add_x_forwarded_for;
proxy_set_header X-Forwarded-Proto $scheme;
proxy_pass http://127.0.0.1:8080;
}
}