Earlier, a guy encountered this problem: He used his HTC phone and he got this error: 0x80072F06 when his windows mobile 6 tried to activsysnc with the local exchange server 2007.
According to MS Technet forums, one of the forummers mentioned that the CA rootchain certificate is need from the SSL provider.
This is because mobile 5, 6, and 6.1 are not up to date on they're root certs so when your Mobile 6 is given the cert from your activesync it doesn't know how to authenicate it to your provider as being real.
You may refer to this: for Windows Mobile 6 Deployment.
- wong chee tat :)
