Problem
Configuring a new VCS connection in Terraform Enterprise fails with a 403 when connecting organization in the TFE UI for VCS connection.
Cause
This is typically caused by the TFE proxy being unable to redirect the browser to the VCS's credentials page properly. Since the user cannot be redirected to the authentication page for the VCS server, the resulting error is `403 Forbidden`
Solutions:
- Add the fully qualified domain name of the VCS server to the TFE proxy exceptions as outlined in this document: https://www.terraform.io/docs/enterprise/install/installer.html#reconfiguring-the-proxy