Connectivity issue with bigquery

Hi all, looking for your help here

  1. My goal: Establish connectivity to google cloud using bigquery from retool. Got the service account created and keys available. Also required firewall and proxy are already open
  2. Issue: 504 gateway timeout issue. Padding to disable msie and chrome friendly error page. Nginx error
  3. Steps I've taken to troubleshoot: formatted the keys shared and tried with different region but nothing helps

Attached error message

Can someone help here please?