Diagnosing Problems with SharePoint Incoming Email

I was recently looking through some old notes about problems I had with incoming email with SharePoint. We had a process of scanning physical mail to departmental document libraries, and we had a success rate of just over 50%. Through a week of tweaking and testing, we sustained 100% successful delivery for several months.

I was using SharePoint 2010 and Exchange 2010, but I think the settings should apply for earlier versions. At the time of writing, I don’t have access to an Exchange installation to confirm settings. These are my rough notes, hopefully of some help.

  1. Check that the document library and contact is set to allow from all senders (network scanners were not regarded as authenticated users)
  2. Check the size limits on the SharePoint send connector (Exchange -> Hub Transport -> Send Connectors -> Properties -> Maximum message size (KB))
  3. Check the size limits on SMTP receiver on SharePoint (IIS 6 Mgr -> Properties on SMTP Virtual Server -> Messages tab -> Limit message size, Limit session size)
  4. Turn off SharePoint reading RTF documents from Exchange (Exchange -> Hub Transport -> Remote Domains -> Format of original message sent as attachment to journal report: -> Exchange rich-text format -> Never use)
  5. Check for potential mail routing problems (Exchange -> Hub Transport -> Accepted Domains -> Add domain for INTERNAL RELAY) – we noticed a couple of times the scanned mail tried to go external through our mail gateway – this was the last 1% of our problems.