Why does Immich work with Docker Compose but not when deployed through Portainer?

Portainer is essentially a management layer on top of Docker, so a valid Compose deployment should behave the same in both places. The most likely difference is how the environment variables are being loaded. Try defining each variable directly in Portainer's environment-variable section instead of relying on an environment file, and double-check paths, database credentials, hostnames, and port mappings. Also compare the generated container configuration and logs between the working and non-working deployments.

Use the platform's official deployment instructions for Portainer rather than assuming the standard Compose file can be pasted in unchanged. Portainer may handle environment files, variable expansion, bind mounts, or stack paths differently depending on how the stack is created. If all services show as running but the page is unreachable, check the Immich server logs and confirm that the expected web port is actually published on the NAS.

The fact that the same files work when launched directly suggests the problem is probably deployment configuration rather than Immich itself. Compare the working containers with the Portainer-created ones: published ports, volume paths, environment values, networks, and the location from which the Compose file is being loaded. A small difference in any of those can leave the services running while making the web interface inaccessible.