Exchange CU5 - Windows Phone 7.8

Hello,

After updating to CU5, Windows Phone 7.8 can't sync anymore to Exchange. ActiveSync is indeed activated. Two kind of errors are reported: 85002028 (it says that Windows Phone is not compatible with this server version) or mail.rabate.fr configuration has a problem (error code 85010004). Same problem with iOS 7.

Any idea on this?

Update

I should have said that Exchange ActiveSync and autodiscovery tests pass (provide that SSL check is deactivated, we have our own PKI)

Thank you