docker-compose: 404 Not Found on start up and die

I use docker-compose. Synapse/Matrix run behind Traefik on the same domain.

- traefik.http.routers.https-synapse.entryPoints=websecure,synapse
- traefik.http.routers.https-synapse.rule=Host(`${CHAT_URL}`) && PathPrefix(`/_matrix`, `/_synapse/`)
- traefik.http.routers.https-synapse.service=synapse
- traefik.http.routers.https-synapse.tls=true
- traefik.http.services.synapse.loadbalancer.server.port=8008
- traefik.http.routers.https-synapse.tls.certResolver=letsencrypt

Normal chat clients (e. g. Element Android, Element Web) can connect and chat on this server.

When I start chatgpt-bot with docker-compose up I get:

matrix-chatgpt-bot  | Sun, 14 May 2023 10:37:39 GMT [ERROR] [MatrixHttpClient] (REQ-1) <html>
matrix-chatgpt-bot  | <head><title>404 Not Found</title></head>
matrix-chatgpt-bot  | <body>
matrix-chatgpt-bot  | <center><h1>404 Not Found</h1></center>
matrix-chatgpt-bot  | <hr><center>nginx/1.23.3</center>
matrix-chatgpt-bot  | </body>
matrix-chatgpt-bot  | </html>
matrix-chatgpt-bot  | 
matrix-chatgpt-bot  | node:internal/process/promises:289
matrix-chatgpt-bot  |             triggerUncaughtException(err, true /* fromPromise */);
matrix-chatgpt-bot  |             ^
matrix-chatgpt-bot  | 
matrix-chatgpt-bot  | [UnhandledPromiseRejection: This error originated either by throwing inside of an async function without a catch block, or by rejecting a promise which was not handled with .catch(). The promise rejected with the reason "#<IncomingMessage>".] {
matrix-chatgpt-bot  |   code: 'ERR_UNHANDLED_REJECTION'
matrix-chatgpt-bot  | }
matrix-chatgpt-bot  | 
matrix-chatgpt-bot  | Node.js v19.9.0
matrix-chatgpt-bot  | info Visit https://yarnpkg.com/en/docs/cli/run for documentation about this command.
matrix-chatgpt-bot  | error Command failed with exit code 1.
matrix-chatgpt-bot exited with code 1

Which page is it trying to access?

matrixgpt / matrix-chatgpt-bot

docker-compose: 404 Not Found on start up and die #169