I was setting up a new client with an Exchange Server, and we discovered that we could not send email to any Microsoft Hosted email addresses. Basically, to a subdomain of Outlook.com. All office 365 hosted email domain are subdomains of this address. The issue was discovered when we tried to send an email manually using a text based email tool. The dialog looks like this (note that the unique data has been modified for privacy): blat.exe -body "this is a test" -to someone@ o365hosted .ca -server o365hosted .mail.protection.outlook.com -f me@legit.ca -s "Test of SMTP" -debug Blat v3.1.1 (build : Feb 27 2013 20:04:23) 32-bit Windows, Full, Unicode << 6:46 +0000 >>>putline>>> EHLO lab1-exch2013 << << ... Text removed for clarity << Sending stdin.txt to someone@ o365hosted .ca Subject: Test of SMTP Login name is Me@legit.ca >>>putline>>> MAIL FROM:< Me@legit.ca > << >>>putline>>...
