Error message "Exchange aborted receiving the message after 2xxxx bytes." - what to do?

If you see the error message Mail transfer to Exchange failed, reason: Exchange aborted receiving the message after ***** bytes. This is probably due to a message size limit in the virtual SMTP server but you are sure it is not the message size limit in the Exchange server receive connector or a firewall then it probably is the Exchange 2007/2010/2013 antispam feature.

Solution for Exchange 2010 and 2007

You need to add your server's IP address to the Exchange IP allow list to solve the problem.

In the Exchange Management Console please go to Server Configuration > Hub Transport > Antispam and add your own server's IP-Address to the IP allow-list.

In very rare cases this might still not be enough. If the problem persists after adding the IP then please go to the *Organisation* Configuration > Hub Transport > Antispam and switch off one antispam rule after the other, testing each time if POPcon can now get through to your Exchangeserver. Once you found the one antispam filter that caused the problem (often it's the "content filtering") then leave that switched off and switch back on all the other filters.

Solution for Exchange 2013

You need to add your server's IP address to the IP allow list your Exchange 2013 by using the Exchange Shell:

Open the Exchange Shell and type in the command:

Please use your own server's IP Address instead of 192.168.1.1 of course.