Hi All, Have been experiencing problems over the last few days. Sometimes when users send an email, it isn't received by the recipient. Some messages will go through, but then some to the exact same address won't. I have looked in the message tracking and the messages that aren't going through don't show up. Does anyone have any idea why this might be happening? I know I haven't given a lot to go on, but any ideas of where to look would be great. The users are using Outlook 2003/2007/2010 and Windows XP/Vista/7, we are running Windows Server 2008 R2 and Exchange 2007. Thanks for any help, Dave.

BUMP

Hello Dave. does the sender get the NDR/DSN report for the they send ? please try creating a new mailbox profile for the sender DhruvDhruv

Hi Dhruv, They don't get any NDR/DSN at all. I will try creating a new mailbox profile. Thanks for the suggestion, any more are appreciated. Dave.

Are the message beong sent internal or external? Are you sure they are not reaching Exch? Have you used MT to confirm this? If you ca reproduce the issue, then try via OWA Try another PC for the problem user. Repair office and test. Try sending in online mode Rebuild the cache and test (delete old OST and create a new one). See if message is stuck in Outbox? Check and see if message is in sent items? Disable any AV on the client and test. Sukh

Hi, Do you have any update? ThanksSophia Xu

I have tried creating a new mailbox profile on all affected machines (5 so far) and it appears not to have worked. One user has reported that some email hasn't been sent this morning. Sukh: 1. External 2. I have used the message tracker to search for messages from the internal sender to the external recipient yes. 3. The error doesn't seem to be reproducable, it seems to happen randomly. 4. Another PC isn't an option as we don't have any spare right now. 5. I will try this, but I can't see how it's affected 5 users at almost the exact same time, using different versions of Windows and 6. What do you mean by "Online Mode"? As in currently connected to exchange? 7. I have switched the affected users to cached mode to see if that makes any difference. 8. I have verified that the message isn't stuck. 9. The message is in sent items. 10. Our entire company runs the same AV, so in theory it should cause problems with everyone or no-one. Thanks for the help so far. I will keep everyone updated.

If you have used message tracking, what does it tell you? Do you get a SEND Event ID? IS it delievred to the next hop as expetced? Did that message leave your gateway? If yes to both of the above, the message could well have been stopped somewhere in the cloud, maybe va your ISP or their ISP, check. Could have been blocked by the recipients gateway/exchange - as their exch admin to check? Ask the recipient to check out on their side, rules, corrupt rules, deleted items, MRM policies etc... If the above 2 points are good, then I'd say issue is either in transit or with the recipients end. Sukh