Eml is functional and working with hundreds of emails per day. I have 2 outside addresses that are both confirmed via hotmail that I rec. the following error on:
a non-delivery report with a status code of 5.4.0 was generated for recipient X
Causes: ....msg. indicates a dns problem or an ip address configuration problem.
solution: check the dns using nslookup or dnsq.....
if i nslookup the domain name my server is able to resolve it back to an ip address. This is only happening to 2 recipient addresses and they are both confirmed.