I am serving hosted Exchange 2010 to my clients. One of my client came with how to use Outlook Express and Windows 7 Mail with Exchange.

I have made researches, read http://technet.microsoft.com/en-us/library/bb124107(v=exchg.141).aspx article and configured my server.

Unfortunatelly POP connection doesn't work. testexchangeconnectivity.com tool errors on ceritificate but nothing should be wrong with certificate or configuration.

Do you see a mistake?

I defined Client Access server as POP and Imap server and Hub Transport server for SMTP.

Pop settings instructions on OWA (4th Edit) Pop settings instructions on OWA

EMS pop settings details (5th Edit) enter image description here

testexchangeconnectivity.com result (4th Edit) testexchange

get-exchangecertificate (1st Post) **get-exchangecertificate**

get-exchangecertificate | fl after UC/SAN certificate installed (5th Edit) enter image description here

get-exchangecertificate | fl after new certificate for pop service installed (4th Edit) get-exchangecertificate | fl

get-exchangecertificate | fl before new certificate for pop service installed (1st Post) get-exchangecertificate

  • Do you have your Exchange certificate assigned to POP? Run Get-ExchangeCertificate and the Services column should have a 'P' under it next to your public-facing Exchange certificate. Jun 19, 2013 at 20:27
  • Yeah. I have P and W under Services
    – aiternal
    Jun 19, 2013 at 21:05
  • have you checked related ports are opened to internet? do you have a firewall? or maybe Windows Firewall? Jun 19, 2013 at 21:41
  • Yes, no firewall. Not only opened the ports, also disabled the firewall.
    – aiternal
    Jun 20, 2013 at 9:05
  • 1
    Two things: 1) follow this article - exchangeserverpro.com/… 2) Do an IISRESET.
    – TheCleaner
    Jun 20, 2013 at 13:28

2 Answers 2


I see the issue...the status for the POP3 cert is INVALID.

enter image description here

Apparently according to Comodo this is a known issue with Exchange 2010 using their "EssentialSSL" cert.

See here: http://forums.comodo.com/ssl-certificate/certificate-is-invalid-for-exchange-server-usage-t86252.0.html

Exchange 2010 does not like the EssentialSSL hierarchy for some reason whereas Exchange 2007 had no issue with it. We recommend that for Exchange 2010 that customers use the Unified Communications certificate from our InstantSSL.com page.

  • Oh my god! I actually ordered a UC/SAN SSL but it is still waiting for validation. Was trying EssentialSSL just for testing. Then I will update my post after getting my UC/SAN SSL. Thank you btw.
    – aiternal
    Jun 20, 2013 at 20:58
  • I just installed SAN certificate but problem still occurs.
    – aiternal
    Jun 20, 2013 at 22:35
  • Can you post the pics again of get-ExchangeCertificate ?
    – TheCleaner
    Jun 21, 2013 at 13:05
  • please search page for after UC/SAN certificate installed
    – aiternal
    Jun 22, 2013 at 6:01

I finally found the solution after weeks.

If you try to connect Exchange Pop service with a third party you should change LoginType @ PopSettings

Set-Popsettings -LoginType plaintextlogin

Don't forget to restart the pop3 service

Thanks busbar@experts-exchange

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