Ggtcf

I use nginx to act as a proxy between 2 servers. I have a domain aswell as a subdomain attached to an ip. I need to send requests to a third ip via a subdomain for convoluted reasons that I wont bore you with.
An issue im having is communication between servers with rest. Any actions I take in my webapp result in

Failed to load resource: net::ERR_CERT_COMMON_NAME_INVALID

Ive been trying to figure it out and I got one login request to pass but after that everything stopped working.

The domain I have setup and everything works fine the subdomain looks like this

server 
 listen 443 ssl; # managed by Certbot
 ssl_certificate /etc/letsencrypt/live/example.com/fullchain.pem; # managed by Certbot
 ssl_certificate_key /etc/letsencrypt/live/example.com/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

 server_name api.example.com www.api.example.com;

 location / 
 proxy_pass "http://x.x.x.x:8080$request_uri";
 proxy_redirect off;
 proxy_http_version 1.1;
 proxy_set_header Host $host;
 proxy_set_header Upgrade $http_upgrade;
 proxy_set_header Connection "upgrade";
 proxy_set_header X-Real-IP $remote_addr;
 proxy_set_header X-Forwarded-For $proxy_add_x_forwarded_for;
 proxy_set_header X-Client-Verify SUCCESS;
 proxy_set_header X-Client-DN $ssl_client_s_dn;
 proxy_set_header X-SSL-Subject $ssl_client_s_dn;
 proxy_set_header X-SSL-Issuer $ssl_client_i_dn;
 proxy_read_timeout 1800;
 proxy_connect_timeout 1800;
 

Im relative new to nginx but to me I think this should work as a proxy. Ive had it call one request but fail there after could it either be a firewall/network issue?