We're seeing an intermittent issue where sometimes emails with attachments are not arriving on the server.
We use an external email scanning solution that is showing the emails as delivered and I've spoken with the support guys for that system that have checked and have said everything is ok there.
On the external system we can redeliver the emails and when doing this they arrive ok so doesn't appear to be an issue with size restrictions on the server.
It's an intermittent issue but one that is hard to track down. Any suggestions?