I'm trying to set up a simple installation of Wordpress using Docker. The Docker Compose file from the official image page works fine, but when I modify it as follows to connect to an external network (which I want to do in order to use an existing caddy-docker-proxy container as a reverse proxy), I get intermittent "Error establishing a database connection" errors: version: '3.1' services: wordpress: image: wordpress restart: always ports: - 8080:80 environment: WORDPRESS_DB_HOST: db WORDPRESS_DB_USER: exampleuser WORDPRESS_DB_PASSWORD: ******** WORDPRESS_DB_NAME: exampledb volumes: - wordpress:/var/www/html networks: caddy: ipv4_address: 172.16.0.30 db: image: mysql:8.0 restart: always environment: MYSQL_DATABASE: exampledb MYSQL_USER: exampleuser MYSQL_PASSWORD: ******** MYSQL_RANDOM_ROOT_PASSWORD: '1' volumes: - db:/var/lib/mysql networks: caddy: ipv4_address: 172.16.0.31 volumes: wordpress: db: networks: caddy: external: true The maddening thing is that while these errors seem to appear on many or most page loads, it often does work fine, and I can get all the way through a basic installation by just tediously refreshing the page every time I see the error. The system is a cheap cloud VM, very lightly loaded. I've looked at the Wordpress and and database logs, but have not found anything. What could the problem be? How can I troubleshoot this further?