502 Bad Gateway sonarr/radarr reverse proxy

[mluker]

My set up:

• I am running docker compose with radarr, sonarr, and nginx proxy manager
• I am using PiHole for DNS, all sites resolve to the correct IP address
• I am running all internal, no outside access
• No changes to the compose setting (posted below)

When I access any of the sites (sonarr/radarr) via IP:port they load quick and everything works. When I use the fqdn (routed through proxy manager) https://sonarr.mydomain.host the site loads very slow and usually throws a bad gateway. The bad gateway comes in the way of the entire request or individual requests. I am forcing SSL, enabled websockets, and enabled HTTP/2. Any ideas on what might cause this sporadic and slow resolution from the proxy?

npm:
container_name: npm
image: 'jc21/nginx-proxy-manager:latest'
restart: always
ports:
# These ports are in format :
- '80:80' # Public HTTP Port
- '443:443' # Public HTTPS Port
- '81:81' # Admin Web Port
volumes:
- ./npm/data:/data
- ./letsencrypt:/etc/letsencrypt
environment:
- PUID=0
- PGID=0
- UMASK=${UMASK:?err}
- TZ=${TIMEZONE:?err}