MDM server certificate is invalid

Hello,

I'm trying to enroll an iPhone 16e as a supervised device in Mobile Device Manager. I don't have ABM/ASM so I'm using Apple Configurator. I've set up the APNs certificate and created a blueprint according to the directions. I can get as far as applying the blueprint (or manually preparing the device, makes no difference) but when I attempt to enroll, I get the message "The configuration for your iPhone could not be downloaded from <organization name>. The MDM server certificate for <enrollment URL> is invalid." I've attached a picture of the error message.

I've attempted enrollment on two different Mobile Device Manager servers and both result in this error message. One of these servers has an iPhone 15 that I enrolled two months ago using this method. Both servers are now running version 11.2.2504.09. The iPhone 15 was enrolled under version 11.2.2500.06, and my first attempt with the iPhone 16e was on version 11.2.2502.11. So it looks like Apple Configurator enrollment broke sometime between those two versions.

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