Survey123 for ArcGIS has been confirmed by multiple customers as working as expected with per app VPN configurations deployed via a mobile device management (MDM). Specific issues still outstanding related to a specific VPN and MDM configuration should be created as a separate bug with detailed information (VPN provider and config, MDM provider and config), OS version and app version and detailed reproduction steps.
解决办法
Deploy directly from the App Store or side load the application.