We are using SimpleMDM to manage iPhones and iPads, and push a Custom Configuration Profile with DNSSettings MDM payload
This DNSSettings payload configures device to use a custom DNS server via HTTPS protocol.
These changes work until the device is restarted. After the restart we can see the profile with DNSSettings payload on the device in Settings > General > VPN, DNS, & Device Management. However, the device is no longer configured to use that custom DNS server, until we un-assign and re-assign the profile on the device.
How can we ensure that a config profile with DNSSettings MDM payload is active on the device even after device restart?
I was trying to get this to work as well, then I found buried in Apple's documentation that when the DNS Settings profile is installed via an MDM, it only works when connected to managed wifi networks.
https://developer.apple.com/documentation/devicemanagement/dnssettings