I have installed iOS 13 Beta 4 on my iPad and trying to enroll to a MDM server which has self signed certificate. The enrollment is throwing out an error that the server certificate is invalid.
I have already installed the trust profile which has the certificate and enable full trust under General - About - Certificate Trust Store settings.
The same device enrolls well when the device is on iOS 12.x but fails to enroll with iOS beta
I found the cause for the issue. This was because the self signed certificate that the MDM server was using was having a life time more than 825 days. As per https://support.apple.com/en-in/HT210176 iOS 13 onwards, this is something that has changed and has cause the trust failure.