Mobility monitor shows "Never Connected (Uninitialized)"

Hello
I have one user (out of many) that have a Galaxy s3 Device.
After adding the user to the data synchronizer and making the initial connection from
the device , everything works fine for a while on the device (mailes & calenders).
But, in the Mobility monitor it shows on the user status "Never Connected (Uninitialized)"
after few hours/days , the sync for this user/device stops to work .
I've removed the user completly (using dsapp) and the problem repets itself.
Help. Thanks.
Beeri