Interesting. I had some initial problems with installing the certificate for blurity.com when I got the intermediate cert chaining backwards, but this is the first I've heard about problems since I fixed that a few months ago.
Could you drop me an email at the address in my profile? Thanks!
A quick Google search turned up this [1], this [2], and this [3], all which seem to indicate that StartCom certificates were unsupported on Windows Phone, at least as of 7.0 RTM. So the problem may indeed be as simple (and frustrating!) as an untrusted root.
Could you drop me an email at the address in my profile? Thanks!