Hello @Mws, I am not sure if it's the same issue, but in my case, the problem occurs because AWS ALB forwards the request to a specific target group along with the defined path pattern.
For example:
https://domain-name/app/metabase is forwarded to http://localhost:3000/app/metabase, but this path is not found in the Metabase app.
To solve this, I set up an Nginx reverse proxy in front of the Metabase app to trim away the target group path before forwarding the request to the Metabase app.
Hope it helps.