502 Bad Gateway

[nckrwlmn]

I keep getting a 502 bad gateway when I try to use the proxy.
Here is the code i am using for the yml file.

version: '3'
services:
app:
image: 'jc21/nginx-proxy-manager:latest'
restart: unless-stopped
ports:
- '80:80'
- '81:81'
- '443:443'
environment:
DB_MYSQL_HOST: "db"
DB_MYSQL_PORT: 3306
DB_MYSQL_USER: "npm"
DB_MYSQL_PASSWORD: "npm"
DB_MYSQL_NAME: "npm"
volumes:
- ./data:/data
- ./letsencrypt:/etc/letsencrypt
db:
image: 'jc21/mariadb-aria:latest'
restart: unless-stopped
environment:
MYSQL_ROOT_PASSWORD: 'npm'
MYSQL_DATABASE: 'npm'
MYSQL_USER: 'npm'
MYSQL_PASSWORD: 'npm'
volumes:
- ./data/mysql:/var/lib/mysql

What could be going on? Ive tried every single tutorial on the internet for this and I cant get it to work on ubuntu 22.