After I upgraded my Domino server on my i5 from Domino 6.0.3 to 6.5.4 I started getting several:Recipient user name Rob Berendt/DEKKO@DEKKO not unique. Several matches found in Domino Directory.
And I stopped getting email. I could duplicate this by sending to myself.
I have a Directory Assistance database that ties my names.nsf to my ldap. And, my ldap is served by another domino server and is composed of the combination of my names.nsf and a duplicate of the names.nsf that only contains ‘web’ users.
The fix was to go into the Configuration document, not the server document, and turn off Exhaustive lookup. Now, neither me, nor the Notes team that I talked to when I opened a pmr, were able to determine why I had this problem on 6.5.4 but not on 6.0.3.