[horde] ActiveSync-ERR: Problem loading mail folders from IMAP server: User is not authorized

["Michael Hübner"]

Hello,

I hope all had a merry christmas. I'm a new user and trying to set up a active-sync server with horde (fresh install from today) to connect a christmas present (HTC Wildfire S) to a private (single-user) emailserver.
I am running Apache/2.2.22 (Debian) DAV/2 PHP/5.4.4-10 mod_ssl/2.2.22 OpenSSL/1.0.1c and managed to set up horde with imp - the web interface is running fine. 


But I am not able to display any message folders on the mobile device - I do not see any mail in the inbox. Sending e-mail with the mobile device and the MS-Exchange profile works fine (althoug I do get an error from the device as the "sent" folder doesn't get updated). 

 testexchangeconnectivity.com gives following error (in German - sorry): 
	Es wird versucht, einen OPTIONS-Befehl an den Server zu senden.
 	Die OPTIONS-Antwort wurde erfolgreich empfangen und ist gültig.

	Es wird versucht, den Befehl 'FolderSync' in der Exchange ActiveSync-Sitzung auszuführen.
 	Fehler beim Testen des Befehls 'FolderSync'.
 	
	Weitere Details
 	Kein Posteingangsordner in der XML-Antwort gefunden.

I enabled error logging on my server, horde logs gives following errors:
DEBUG: [26431] Initializing folder diff engine
DEBUG: Horde_Core_ActiveSync_Driver::getFolderList()
DEBUG: Polling Horde_Core_ActiveSync_Driver::_getMailFolders()
ERR: Problem loading mail folders from IMAP server: User is not authorized
ERR: User is not authorized
DEBUG: [26431] No folder changes found.


I did read the note "RewriteRule .* - [E=HTTP_MS_ASPROTOCOLVERSION:%{HTTP:Ms-Asprotocolversion}] etc." info on the horde-wiki but that doesnt seem to help or change anything.

I am really struggeling where the problem could be, if anybody could give me a hint where to look for I would be very glad, mailing list / web search didnt help me.

Best regards,
Michael Huebner