Notifications to Gotify Erroring Out Due to Invalid Character

[uninvitedguest]

Describe the bug

Watcher used to run and send notifications. It stopped a few weeks back and I only just noticed. The compose.yaml hasn't changes from the time it was working.

version: '1'
services:
  watchtower:
    image: containrrr/watchtower
    container_name: watchtower
    volumes:
      - /var/run/docker.sock:/var/run/docker.sock
    environment:
      - TZ=America/Toronto      
      - WATCHTOWER_RUN_ONCE=true
      - WATCHTOWER_MONITOR_ONLY=true
      - WATCHTOWER_CLEANUP=true
      - WATCHTOWER_POLL_INTERVAL=172800 #86400 (24 hours)
      - WATCHTOWER_NOTIFICATIONS=gotify
      - WATCHTOWER_NOTIFICATION_GOTIFY_URL=https://<secret>
      - WATCHTOWER_NOTIFICATION_GOTIFY_TOKEN=<secret>
      - WATCHTOWER_DEBUG=true

Steps to reproduce

1. Run docker compose up -d
2. Check logs
3. See error

Expected behavior

I expect to see notifications on my Gotify server.

Screenshots

No response

Environment

• Debian
• AMD64
• Docker Version 1.5.3

Your logs

time="2023-09-05T21:26:24Z" level=error msg="Failed to send shoutrrr notification" error="failed to send notification to Gotify: invalid character '<' looking for beginning of value" index=0 notify=no service=gotify

Additional context

No response

[github-actions]

Hi there! 👋🏼 As you're new to this repo, we'd like to suggest that you read our code of conduct as well as our contribution guidelines. Thanks a bunch for opening your first issue! 🙏

[piksel]

That error message looks like the outcome of the go JSON deserializer getting HTML input. Not entirely sure why that is happening though...

My guess is that it's not reaching the gotify server, and instead getting the response from some other server (or perhaps a proxy, like nginx?).

I really think shoutrrr ought to add some context to that error message though...

[uninvitedguest]

Thanks @piksel, that's right. It is hitting NGINX proxy manager first. Websocket support is enabled.