Originally Posted by Sergey_Kashin

Hello, sorry that missed your post
Can you enable the ActiveSync logs, reproduce this issue and attach logs? Please make sure that Extended logging is enabled:
[ExtendedLog]
Enabled=1

In addition, can you sync your Sent Items folder and copy an extended log part here with something like (or just attach all activesync logs and tell me the subject of the sent message):

Dec 29 17:26:29 (none) activesync[4248]: [Debug] General : AsProtocol job AsProtocolJob(0x537c38) , received a response, http status 200
Dec 29 17:26:29 (none) activesync[4248]: [Debug] AS_LIB : <AirSync::Sync>
.................................................. .................
Dec 29 17:26:29 (none) activesync[4248]: [Debug] AS_LIB : <AirSync::ApplicationData>
Dec 29 17:26:29 (none) activesync[4248]: [Debug] AS_LIB : <Email::To>"Sergey Kashin" <somemail@server.com></Email::To>
Dec 29 17:26:29 (none) activesync[4248]: [Debug] AS_LIB : <Email::From>"somemail2@server.com" <somemail2@server.com></Email::From>
Dec 29 17:26:29 (none) activesync[4248]: [Debug] AS_LIB : <Email::Subject>Just a simple new email</Email::Subject>
Dec 29 17:26:29 (none) activesync[4248]: [Debug] AS_LIB : <Email:ateReceived>2011-12-29T13:25:02.132Z</Email:ateReceived>
Dec 29 17:26:29 (none) activesync[4248]: [Debug] AS_LIB : <Email:isplayTo>Sergey Kashin</Email:isplayTo>
Dec 29 17:26:29 (none) activesync[4248]: [Debug] AS_LIB : <Email::ThreadTopic>Just a simple new email</Email::ThreadTopic>
Dec 29 17:26:29 (none) activesync[4248]: [Debug] AS_LIB : <Email::Importance>1</Email::Importance>
Dec 29 17:26:29 (none) activesync[4248]: [Debug] AS_LIB : <Email::Read>0</Email::Read>
Dec 29 17:26:29 (none) activesync[4248]: [Debug] AS_LIB : <AirSyncBase::Body>
Dec 29 17:26:29 (none) activesync[4248]: [Debug] AS_LIB : <AirSyncBase::Type>2</AirSyncBase::Type>
Dec 29 17:26:29 (none) activesync[4248]: [Debug] AS_LIB : <AirSyncBase::EstimatedDataSize>653</AirSyncBase::EstimatedDataSize>
Dec 29 17:26:29 (none) activesync[4248]: [Debug] AS_LIB : <AirSyncBase:ata>*** too long (653 characters) ***</AirSyncBase:ata>
Dec 29 17:26:29 (none) activesync[4248]: [Debug] AS_LIB : </AirSyncBase::Body>
Dec 29 17:26:29 (none) activesync[4248]: [Debug] AS_LIB : <Email::MessageClass>IPM.Note</Email::MessageClass>
Dec 29 17:26:29 (none) activesync[4248]: [Debug] AS_LIB : <Email::InternetCPID>65001</Email::InternetCPID>
Dec 29 17:26:29 (none) activesync[4248]: [Debug] AS_LIB : <Email::Flag/>
Dec 29 17:26:29 (none) activesync[4248]: [Debug] AS_LIB : <Email::ContentClass>urn:content-classes:message</Email::ContentClass>
Dec 29 17:26:29 (none) activesync[4248]: [Debug] AS_LIB : <AirSyncBase::NativeBodyType>2</AirSyncBase::NativeBodyType>
Dec 29 17:26:29 (none) activesync[4248]: [Debug] AS_LIB : </AirSync::ApplicationData>
.................................................. .......................................
Dec 29 17:26:29 (none) activesync[4248]: [Debug] AS_LIB : </AirSync::Sync>
Dec 29 17:26:29 (none) activesync[4248]: [Debug] AS_LIB : SUCCESS status received when synchronizing server changes in folder 8


P.S. Don't forget to remove all your private info from the logs.