SSL behind NGINX reverse proxy domain and a port

[nine-2-five]

When I connect to local LAN server using port 8000, then connection goes through and I can access and create an S3 bucket.
However when I connect through s3.example.com:10000 I get: "The request signature we calculated does not match the signature you provided."
When the URL is opened in browser the xml is displayed, so the network visibility is there.
The only modification to the config.json is the addition of "s3.example.com": "us-east-1" in the restEndpoints property. I've tried specifying "s3.example.com:10000": "us-east-1", but it didn't work.

[nine-2-five]

It seems there is an issue with NGINX, I tried the same setup with HAProxy and it worked after some tweaking with the certificates.