AssetTrack user devices communicate with an AssetTrack or a ServiceNow instance using https. Any AssetTrack device wishing to access an AssetTrack Server or a ServiceNow instance must have unfiltered https access. This connectivity can be over LTE, wifi, VPN or via a proxy server.
If you implement a proxy server between the device and an AssetTrack Server or ServiceNow instance the proxy must proxy the entire request. Do not filter or modify the requests in any way or you risk breaking application functionality.