Changes have been made in Git (master):

commit 1bc61ce1be9e2dbb603c98285efcfe2c5f231948
Author: Jan Schneider <jan@horde.org>
Date:   Tue Sep 16 14:27:42 2014 +0200

     [jan] Catch exceptions if not being able to find an LDAP user DN 
(Bug #13571).

  framework/Core/lib/Horde/Core/Factory/Ldap.php |   16 +++++++++++-----
  framework/Core/package.xml                     |    2 ++
  2 files changed, 13 insertions(+), 5 deletions(-)

http://github.com/horde/horde/commit/1bc61ce1be9e2dbb603c98285efcfe2c5f231948

This is really easy to fix. the fix is do not try findUserDN as long 
as no username is known. The fix must go into 
/usr/share/pear/Horde/Core/Factory/Ldap.php

See appended patch

Since Update to 5.2.1 our previously working Active Sync Configuration 
does not work anymore.

In the logs we see this:

2014-09-16T09:45:22+02:00 DEBUG: HORDE Load config file (conf.php; 
app: horde) [pid 12591 on line 109 of 
"/usr/share/pear/Horde/Registry/Loadconfig.php"]
2014-09-16T09:45:22+02:00 DEBUG: HORDE Load config file (hooks.php; 
app: horde) [pid 12591 on line 109 of 
"/usr/share/pear/Horde/Registry/Loadconfig.php"]
2014-09-16T09:45:22+02:00 DEBUG: HORDE Setting sam inactive because 
the fileroot does not exist or the application is not configured yet. 
[pid 12591 on line 139 of 
"/usr/share/pear/Horde/Registry/Registryconfig.php"]
2014-09-16T09:45:22+02:00 DEBUG: HORDE Setting ansel inactive because 
the fileroot does not exist or the application is not configured yet. 
[pid 12591 on line 139 of 
"/usr/share/pear/Horde/Registry/Registryconfig.php"]
2014-09-16T09:45:22+02:00 DEBUG: HORDE Setting wicked inactive because 
the fileroot does not exist or the application is not configured yet. 
[pid 12591 on line 139 of 
"/usr/share/pear/Horde/Registry/Registryconfig.php"]
2014-09-16T09:45:22+02:00 DEBUG: HORDE Setting chora inactive because 
the fileroot does not exist or the application is not configured yet. 
[pid 12591 on line 139 of 
"/usr/share/pear/Horde/Registry/Registryconfig.php"]
2014-09-16T09:45:22+02:00 DEBUG: HORDE Setting whups inactive because 
the fileroot does not exist or the application is not configured yet. 
[pid 12591 on line 139 of 
"/usr/share/pear/Horde/Registry/Registryconfig.php"]
2014-09-16T09:45:22+02:00 DEBUG: HORDE Setting luxor inactive because 
the fileroot does not exist or the application is not configured yet. 
[pid 12591 on line 139 of 
"/usr/share/pear/Horde/Registry/Registryconfig.php"]
2014-09-16T09:45:22+02:00 DEBUG: HORDE Setting klutz inactive because 
the fileroot does not exist or the application is not configured yet. 
[pid 12591 on line 139 of 
"/usr/share/pear/Horde/Registry/Registryconfig.php"]
2014-09-16T09:45:22+02:00 DEBUG: HORDE Setting jonah inactive because 
the fileroot does not exist or the application is not configured yet. 
[pid 12591 on line 139 of 
"/usr/share/pear/Horde/Registry/Registryconfig.php"]
2014-09-16T09:45:22+02:00 DEBUG: HORDE Setting hermes inactive because 
the fileroot does not exist or the application is not configured yet. 
[pid 12591 on line 139 of 
"/usr/share/pear/Horde/Registry/Registryconfig.php"]
2014-09-16T09:45:22+02:00 DEBUG: HORDE Setting sesha inactive because 
the fileroot does not exist or the application is not configured yet. 
[pid 12591 on line 139 of 
"/usr/share/pear/Horde/Registry/Registryconfig.php"]
2014-09-16T09:45:22+02:00 DEBUG: HORDE Setting kolab inactive because 
the fileroot does not exist or the application is not configured yet. 
[pid 12591 on line 139 of 
"/usr/share/pear/Horde/Registry/Registryconfig.php"]
2014-09-16T09:45:22+02:00 DEBUG: HORDE Setting agora inactive because 
the fileroot does not exist or the application is not configured yet. 
[pid 12591 on line 139 of 
"/usr/share/pear/Horde/Registry/Registryconfig.php"]
2014-09-16T09:45:22+02:00 DEBUG: HORDE Setting ulaform inactive 
because the fileroot does not exist or the application is not 
configured yet. [pid 12591 on line 139 of 
"/usr/share/pear/Horde/Registry/Registryconfig.php"]
2014-09-16T09:45:22+02:00 DEBUG: HORDE Setting vilma inactive because 
the fileroot does not exist or the application is not configured yet. 
[pid 12591 on line 139 of 
"/usr/share/pear/Horde/Registry/Registryconfig.php"]
2014-09-16T09:45:22+02:00 DEBUG: HORDE Load config file (nls.php; app: 
horde) [pid 12591 on line 109 of 
"/usr/share/pear/Horde/Registry/Loadconfig.php"]
2014-09-16T09:45:25+02:00 EMERG: HORDE [horde] DN for user  not found 
[pid 12591 on line 886 of "/usr/share/pear/Horde/Ldap.php"]
2014-09-16T09:45:25+02:00 DEBUG: HORDE  1. 
Horde_Injector->getInstance() /var/www/html/horde/rpc.php:101
  2. Horde_Injector->createInstance() /usr/share/pear/Horde/Injector.php:258
  3. Horde_Injector_Binder_Factory->create() 
/usr/share/pear/Horde/Injector.php:224
  4. Horde_Core_Factory_ActiveSyncServer->create() 
/usr/share/pear/Horde/Injector/Binder/Factory.php:111
  5. Horde_Injector->getInstance() 
/usr/share/pear/Horde/Core/Factory/ActiveSyncServer.php:17
  6. Horde_Injector->getInstance() /usr/share/pear/Horde/Injector.php:253
  7. Horde_Injector->createInstance() /usr/share/pear/Horde/Injector.php:258
  8. Horde_Injector_Binder_Factory->create() 
/usr/share/pear/Horde/Injector.php:224
  9. Horde_Core_Factory_ActiveSyncBackend->create() 
/usr/share/pear/Horde/Injector/Binder/Factory.php:111
10. Horde_Core_Factory_ActiveSyncBackend->_getAuth() 
/usr/share/pear/Horde/Core/Factory/ActiveSyncBackend.php:28
11. Horde_Core_Factory_Auth->create() 
/usr/share/pear/Horde/Core/Factory/ActiveSyncBackend.php:44
12. Horde_Core_Factory_Auth->_create() 
/usr/share/pear/Horde/Core/Factory/Auth.php:54
13. Horde_Core_Factory_Ldap->create() 
/usr/share/pear/Horde/Core/Factory/Auth.php:159
14. Horde_Ldap->findUserDN() /usr/share/pear/Horde/Core/Factory/Ldap.php:81


It looks like findUserDN is called somewhere during the activesync 
connect where a username is not yet known. This was during a try to 
create a new Exchange Account on a Android device. Also existing 
Accounts do not work anymore.