[horde] ActiveSync disappearing and reappearing contacts

[Matthias Marx]

Hi everyone,

I have a strange problem with ActiveSync since a while but ignored it  
since CardDav syncing is working as a workaround. Maybe someone has  
the same issue or could point me in the right direction what's wrong  
with my installation.

I have a very small horde installation where I used only one account  
since a couple of years, this account is working fine. Recently I  
added more user accounts, including a brand new test account, and they  
are experiencing the following issue.

When I add the test account as and Exchange Account on a Nexus 5 or  
Nexus 9 device the setup process is working fine. I'm using a self  
signed certificate so I accept all SSL certificates during the setup  
process and I'm currently only testing contacts syncing.
The contact syncing seems to work correctly and the contacts appear in  
the devices address book but on the next sync operation all contacts  
vanish from the device, they are still on the server(horde  
webinterface) though. On the next sync all contacts reappear in the  
address book, it's like toggling between "no contacts" and "all  
contacts" between sync events. I also tried creating contacts on the  
device while it was showing "no contacts" or "all contacts" but after  
the next sync event those contacts are gone and they are not synced to  
horde.
I have even seen, when I have a lot of contacts in the address book,  
that the horde contacts appear one by one in devices address book  
while it is syncing and at the end of the sync process, at the moment  
it is finished, all contacts disappear from the device.

On a side note, for the calendar it is something similar. While the  
device is syncing I see(can select) the test account calendar appear  
in the calendar App but as soon as the syncing finishes the calendar  
disappears from the device.

Here is the ActiveSync log of two syncs:
http://netdmon.de/public/2015-07-08_horde_active_sync.txt

There are no errors in the horde logfile, just the notice that the  
user login succeeded.

If you need more information please ask. I can also provide access to  
the test account and the ActiveSync log but not publicly.

Kind Regards

Matthias Marx