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.
- Check that the document library and contact is set to allow from all senders (network scanners were not regarded as authenticated users)
- Check the size limits on the SharePoint send connector (Exchange -> Hub Transport -> Send Connectors -> Properties -> Maximum message size (KB))
- 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)
- 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)
- 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.