I viewed the other link but no help. Here is my issue, only when sending new meeting requests or invites I get the above mentioned error. 550 4.4.7 QUEUE.Expired My setup as follows, Server 2012 , Exchange 2013 I can telnet to the mail.domain.com 25 Again this only happens when i try to send calender requests Diagnostic information for administrators: Generating server: domain.local #550 4.4.7 QUEUE.Expired; message expired ## Received: from domain.local (10.1.0.232) by domain.local (10.1.0.232) with Microsoft SMTP Server (TLS) id 15.0.516.32; Fri, 3 May 2013 12:09:33 +0200 Received: from domain.local ([fe80::b564:f085:a8f2:145b]) by domain.local ([fe80::b564:f085:a8f2:145b%12]) with mapi id 15.00.0516.029; Fri, 3 May 2013 12:09:33 +0200 Content-Type: application/ms-tnef; name="winmail.dat" Content-Transfer-Encoding: binary From: User@domain.com> To: User@domain.com Subject: Online Systems Thread-Topic: Online Systems Thread-Index: Ac5H4f5gxTOOCpaRRAaDWHMdTJxJogAA+uZA Date: Fri, 3 May 2013 12:09:32 +0200 Message-ID: <c63f24d0f51941bd8cecea624ad8a742@ONLINEXCH1.OnlineIntelligencePtyLtd.local> Accept-Language: en-US, en-ZA Content-Language: en-US X-MS-Has-Attach: yes X-MS-TNEF-Correlator: <c63f24d0f51941bd8cecea624ad8a742@ONLINEXCH1.OnlineIntelligencePtyLtd.local> MIME-Version: 1.0 X-Originating-IP: [10.1.1.220] Return-Path: User@domain.com X-EsetResult: clean, is OK X-EsetId: 1961053D22C734334D265E

Hi This problem occurs because the email message in the queue expired. In this situation, the sending server tries to relay or deliver the email message. However, the action is not completed before the message expiration time occurs. From "Understanding Non-Delivery Reports" http://technet.microsoft.com/en-us/library/bb232118(EXCHG.80).aspx The message in the queue has expired. The sending server tried to relay or deliver the message, but the action was not completed before the message expiration time occurred. This message can also indicate that a message header limit has been reached on a remote server, or some other protocol time-out occurred while communicating with the remote server. This message usually indicates an issue on the receiving server. Check the validity of the recipient address, and determine if the receiving server is configured correctly to receive messages. You may have to reduce the number of recipients in the message header for the host about which you are receiving this error. If you send the message again, it is placed in the queue again. If the receiving server is available, the message is delivered. Hope it will help Cheers Zi Feng TechNet Community Support

I only send to one user?

I'm having the same issue as JacoOnline, and Zi Feng is not reading (or believing) the full information that JacoOnline has provided. This *only* occurs with meeting invitations. And it occurs with *all* meeting invitations to external recipients. If we send a normal email to the very same recipient/s, it will go through happily. Let me reiterate - emails will be successfully delivered to the recipients without any problem. But if we send a meeting invitation to the same recipient, it will consistently bounce. I understand the message in the queue has expired (in fact the bounce message tells us this). But we don't yet know the reason why. And it's not because of the recipient's server. And it's not to do with the number of recipients (even with just 1 recipient it bounces). There is an issue, probably to do with our configuration, which we've not yet been able to identify. We host 6 domains on our server which mostly are used as multiple aliases for our users (e.g. company.com, company.com.au, companygroup.com, companygroup.com.au, domain.local). We used to have an SBS2011 server and we did an inplace migration across to Server 2012 + Exchange 2013, then we finally retired our SBS2011 system. There's a possibility that something is still looking for or trying to route through the old server SBS01, but we don't understand it well enough and haven't yet been able to identify if this is the case. **Extra note** After a bit more testing, I've identified that is also only affects certain users. Cheers

I am having the same problem, only happens with meeting requests. Brand new 2012 domain with Exchange 2013, no legacy points to factor in.