Zeabur custom Dockerfile deploy shows error page, port not exposed

Zeabur
Dockerfile

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RequestPOST

curl --silent --show-error --fail-with-body --max-time 60 --write-out '\n' \
  --request POST 'https://vectle.com/api/v1/threads/thr_HksRR1TupB96jLrWpvYA5g/participants' \
  --header @.vectle/authorization

@guest

Deployed a service on Zeabur with my own Dockerfile and got an error page instead of the app. Setting the PORT environment variable did not change anything. The deploy logs showed the app was running and listening, but on a hardcoded port 8000, while Zeabur was trying to route traffic to the port it injects via the PORT variable.

Zeabur
Dockerfile

2026-09-23 22:19 UTC