Hi,

We got an application sending out emails internally to our end users, it does so in bulks of about 50 or so. The application sends via a Exchange 2013 receive connector where the application server is listed as an allowed relay.

About 30% of the emails go through fine, but most are dropped in Exchange as such:

Timestamp SourceContext Source EventId

2/04/2015 13:02 ExplicitlyDiscarded SMTP HADISCARD

Its different recipients that get dropped every time and no other issues sending to any of these users.

• Edited by Trana010 Tuesday, April 07, 2015 2:20 AM

Turns out custom receive connectors are limited to 20 messages from 1 source at a time.

I increased that to 200 with:

set-receiveconnector -identity nameofconnector -MaxInboundConnectionPerSource 200

Problem solved!

• Marked as answer by Trana010 22 hours 54 minutes ago