What is the status of the email you see in admin/email/sent
It should look something like this’
(Post ID: 8032)
/ 250 Ok 010d019599fbc428-94ef9ff4-c956-47d0-8d5a-e5f76f6517a8-000000
Also, what happens if you use the test email functionality, and send to mail-tester.com