iOS devices no longer enrolling

[ICTSS]

Hi, we have been enrolling some old iPad 2s and with one left to be enrolled, we are now getting an error message when attempting to install the MDM Profile. The error message states either "A network error has occurred" or "The enrolment server did not provision a valid identity certificate". I am tying myself in knots retracing steps to work out what has gone wrong; I have been told "a certificate" was renewed as it was about to expire, but no more information than that. Would really appreciate any advice.

[mjsanders]

Have you seen the change in iOS 10.3 to not accept self-signed certificates?
jamf kbase article

[ICTSS]

I had not seen this, so thank you for pointing it out, although sadly it is not to blame for this problem - the iPad 2s won't run anything above iOS 9.3.5.

Thanks again for pointing out about the self-signed certs on 10.3 though, I shall bear it in mind for any newer devices we have.