Kopano SendAs in Outlook problem sincs Upgrade to UCS 4.3


I’ve problem with send as funktion from outlook with KOE since upgrade to UCS 4.3 I get this error in kopano spooler.log:

Wed Apr 11 17:12:29 2018: [error  ] [40221] HRESULT SMTPToZarafa(LPADRBOOK, ULONG, const ENTRYID*, ULONG*, ENTRYID**): ResolveName failed: not found (8004010f)

Wed Apr 11 17:12:29 2018: [error  ] [40221] User "Christian Kraus" is not allowed to send as user or group "officeckc@MAILSERVERNAME.domain.local". You may enable all outgoing addresses by enabling the always_send_delegates option.

the officeckc@MAILSERVERNAME.domain.local should be officeckc@maildomain

I get this if send/reply from shared mailbox as delegate with own user address in sender field, if selecting the sharedmailboxuseraddress (officeckc@maildomain) as sender address it works

Does anyone have same issue or a hint on where I may look for to resolv this ?

I’ve first thought it’s problem after z-push Upgrade and did a post on Kopano Forum too - but after further investigations from me it seems not to be z-push as this was updated in front of UCS 4.3 Upgrade -maybe a problem with the new postfix version ?