set GF_SERVER_ROOT_URL as ${PROXY_URL}/visualization/
With the current configuration GF_SERVER_ROOT_URL=%(protocol)s://%(domain)s/visualization/ grafana redirects to localhost for Oauth Login.
This was not a problem for local testing but AAI login did not work on the intranet VM.
Fixed by replacing it with GF_SERVER_ROOT_URL=${PROXY_URL}/visualization/