AppAPI Deploy Daemon “not accessible” in Synology+Docker despite healthy container and curl OK

Describe the bug

After deploying AppAPI daemon via Docker under Synology, the daemon appears healthy in Portainer, responds correctly with curl using basic auth, but the Nextcloud

and test connection fails.

Steps/Code to Reproduce

What works

• curl -u app_api_haproxy_user:MI_CLAVE http://127.0.0.1:5013/_ping → OK

What fails

• Nextcloud always shows “Failed to connect to Daemon. Check logs”
• Logging (settings/admin/logging) shows:
• ConnectException cURL error 7: Failed to connect to 127.0.0.1 port 5013
• Deploy daemon "harp_proxy_host" is not accessible by Nextcloud...

What I’ve tried

• Verified every field and protocol, restarted containers, updated Nextcloud, tried from different browsers.
• AppAPI does not show updates in “Aplications”.
• Daemon and Nextcloud runs as root/http, no firewall blocks, Synology ports OK.

Suspected bug

• Similar to #153, but persists in new versions and not solved by changes or restarts.
• The shared key is correctly stored, proven by curl, but the panel cannot connect.

Steps to reproduce

1. Deploy AppAPI daemon as above.
2. Register and test in Nextcloud config panel using described fields.
3. Observe error, although direct curl OK

Expected Results

Expected behavior
Daemon should be reachable for Nextcloud if curl from host is OK and daemon shown “healthy”.

Actual Results

admin panel always shows "Daemon not accessible"

Setup configuration

Versions

• Nextcloud version: 32.0.0
• AppAPI version: 3.2.3
• Daemon Docker image: ghcr.io/nextcloud/nextcloud-appapi-dsp:release
  System details
• Synology NAS (describe tu modelo), Docker, Portainer
• Nextcloud running in [Docker/native]
• Daemon command docker run -e NC_HAPROXY_PASSWORD="MI_CLAVE"
  -v /var/run/docker.sock:/var/run/docker.sock
  --name nextcloud-appapi-dsp
  --restart unless-stopped --privileged
  -p 5013:2375
  -d ghcr.io/nextcloud/nextcloud-appapi-dsp:release
• Daemon state: “healthy” in Portainer

Config in Nextcloud

• "Servidor HaRP": http://127.0.0.1:5013
• "Clave compartida": [same to daemon]
• "docker-install", net bridge

Start with the AppAPI configuration panel and the logging output described in the issue, then compare its connection attempt with the successful curl request to /_ping. Review the Docker command, port mapping, and configured HaRP server value. Done means the Nextcloud test connection succeeds for this Synology and Docker setup.