Too many redirect with Nginx and subdomain

Hi! I’m completely new to Nginx and followed DigitalOcean’s tutorial on how to set it up with LetsEncrypt! I must have done something wrong though because I am getting a ERR_TOO_MANY_REDIRECTS message when navigating to the site. Not sure if it makes a difference, but the redirect is for a subdomain (strapi.mysite.com). There is no config for the root domain mysite.com yet.

I have the following config in /etc/nginx/sites-available/mysite.com:

server {
    # Listen HTTP
    server_name strapi.mysite.com;


    location / {
        proxy_pass http://strapi;
        proxy_http_version 1.1;
        proxy_set_header X-Forwarded-Host $host;
        proxy_set_header X-Forwarded-Server $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 $scheme;
        proxy_set_header Host $http_host;
        proxy_set_header Upgrade $http_upgrade;
        proxy_set_header Connection "Upgrade";
        proxy_pass_request_headers on;
    }

    listen 443 ssl; # managed by Certbot
    ssl_certificate /etc/letsencrypt/live/strapi.mysite.com/fullchain.pem; # managed by Certbot
    ssl_certificate_key /etc/letsencrypt/live/strapi.mysite.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 {
    if ($host = strapi.mysite.com) {
        return 301 https://$host$request_uri;
    } # managed by Certbot


    listen 80;
    server_name strapi.mysite.com;
    return 404; # managed by Certbot


}

I’m not quite sure what I did wrong here. I do not see an obvious loop, but perhaps it’s my inexperience with Nginx. Any ideas?