Mails from O365 via DMZ Postfix Server to Coex Server will not be delivered to Lotus Notes (4306445)

Mails from O365 via DMZ Postfix Server to Coex Server will not be delivered to Lotus Notes

Mails from O365 via DMZ-Postfix Server to Coex-Server will not be delivered to Lotus Notes. Mails stuck on the Postfix Server and could not finally deliverd. I enabled verbose logging on COEX Server with mail connector. I could see, that SMTP-Connection is successfull, but the final data Transfer failed. Attached my verbose log entries: 2015-06-10 15:30:46,951 WARN logging [Proxy 5] - Message Number [5] on Thread [17] from Exchange (62.180.227.193:63811) to Domino (172.16.13.226:25): A communications failure or interuption was encountered. - IOException: Unable to read data from the transport connection: A connection attempt failed because the connected party did not properly respond after a period of time, or established connection failed because connected host has failed to respond Stack Trace: at System.Net.Sockets.NetworkStream.Read(Byte[] buffer, Int32 offset, Int32 size) at Dell.Base.Networking.SecureSocket.Read(Byte[] buffer, Int32 offset, Int32 count) at Dell.Base.Networking.SecureSocket.Read(Byte[] buffer) at Dell.CMX.API.Core.Networking.Smtp.ServerProtocol.ReceiveMessageBody(TempStream stream) at Dell.CMX.API.Core.Networking.Smtp.ServerProtocol.ReceiveMessageBody() at Dell.CMX.API.Core.Networking.Smtp.Proxy.ReceiveMessageBodyAndProcess(ServerProtocol server, Boolean messageIsDsn) at Dell.CMX.API.Core.Networking.Smtp.Proxy.Run() at Dell.CMX.API.Core.Networking.Smtp.Proxy.b__0( SocketException: A connection attempt failed because the connected party did not properly respond after a period of time, or established connection failed because connected host has failed to respon Stack Trace: at System.Net.Sockets.Socket.Receive(Byte[] buffer, Int32 offset, Int32 size, SocketFlags socketFlags) at System.Net.Sockets.NetworkStream.Read(Byte[] buffer, Int32 offset, Int32 size) A mail delivery from Postfix Server via Telnet and core SMTP-Commands are succesfull. Only regular mails stuck and will be not delivered