Email shows as sent, but does not deliver in Exchange 2010 office 365 hybrid

We just transitioned to Exchange 2010 Office 365 Hybrid.  About once a day the Exchange server needs to be rebooted, as emails show up in users sent items but do not deliver.  They are also unable to receive email.  Once the server is rebooted, everything comes through.  I did not see anything in Errors in the Event Viewer that seemed to correspond with the timing of this issue.  I reviewed the firewall logs and found nothing useful.  Any ideas as to what could be causing this daily annoyance?
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Currently there are a lot of issues with older Exchange versions transport stop delivering emails.  See here:¬ificationFollowed=209874173#a42625261

Installing recent updates is worth a shot but doesn't guarantee a solid fix.  Still waiting to hear from anyone having a solid fix.
AmitIT ArchitectCommented:
Scott CSenior EngineerCommented:
We have a few reports the July security update causing issues with some network services. We are still looking into this and will keep you updated. In the meantime I would recommend removing the following updates.

July Security-only Update
KB4338823 (Server 2008 R2)
KB4338820 (Server 2012)
KB4338824 (Server 2012 R2)

July Monthly Rollup (Sec included)
KB4338818 (Server 2008 R2)
KB4338830 (Server 2012)
KB4338815 (Server 2012 R2)

Check to see if you have any of the above updates recently installed.  What you are describing is what we are starting to see.

I sent this to one of my customers just today.

Another co-worker has a customer with the exact same thing.

This is a known issue with Microsoft.

What is going on is that there are only so many sockets available and depending on usage, is when the sockets are used up, they are not released.  Kind of like a memory leak.

Make sure the updates are completely removed.

I just checked with our EE engineers and a patch for the patch is currently being worked on.

You'll never guess who I do Exchange Support for. ;-)

Also...see this thread...¬ificationFollowed=209868595#a42625133

Also remove KB4339093 and KB4338420.
There are reports that these updates may be causing issues as well.


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dchevalierAuthor Commented:
Thank you all for helping. It did turn out to be a set of junky updates that we had to roll back and then replace with "newly minted" updates. Thank you for the help.
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