Windows Phone 8.1 Update 1 Problems

[bilbo_b]

If i use my Windows Phone to connect to Open Change Server (Strato) and i use the Push Service, i get the Errorcode 0. However all Content seems to be synced correctly. It seems, if i use sync via Interval the Sync works.

The Problem occurs with Windows Phone 8.1 Update 1 (Developer Preview). Server is the Strato Server in Germany (7.4.2-Rev27).

Do you have any idea, how to fix the problem?