I run a DNSReport.com test for my domain name and it failed on "Mail" section with this error message:
ERROR: I could not complete a connection to any of your mailservers!
my-domain.com: Timed out [Last data sent: RCPT TO: ]
If this is a timeout problem, note that the DNS report only waits about 40 seconds for responses, so your mail *may* work fine in this case but you will need to use testing tools specifically designed for such situations to be certain.
also on DNSReport.com mail test, got this error message:
my-domain.com. - xxx.xxx.xxx.xxx [Could not connect: Could not receive data: Operation timed out.]
[Note that if your mailserver takes over 30 seconds to respond, our test will timeout, even though real mailservers will wait longer]
what makes my server failed on this test? please advise