Exchange account set-up missing for Outlook 2016

Ok, so after nearly three (3) hours on the phone with Microsoft, I was able to get the issue fixed. This is what I did...

Open "regedit"

Navigate to "HKEY_CURRENT_USER\SOFTWARE\Microsoft\Office\16.0\Outlook\AutoDiscover"

On the right, right-click, select "New" -> "DWORD (32-bit) Value"

Name it "ExcludeHttpsRootDomain"

Double-click the value after adding and set "Value data" to "1" and leave Base as Hexadecimal

What was causing the issue...

Evidently the root domain server was actually responding to the "autodiscover" request so outlook never made it to "AutoDiscover.[Domain.com]", it held up at "[Domain.com]:443". By adding this registry entry, it is telling outlook to ignore the root domain and go directly to the next option on the list (e.g. "Autodiscover.[Domain.com]".

Hopefully this will help someone else having a similar issue.

Interesting.  Thanks for the info.  I ran some autodiscover tests on our domain....

1. Failed on https://<domain>:443/Autodiscover/Autodiscover.xml.  Makes sense as I didn't set my root domain to redirect to Microsofts servers.  Nor should I have to.  They're just hosting my email.
2. Failed on https://autodiscover.<domain>:443/Autodiscover/Autodiscover.xml.  This doesn't seem good as I have a CNAME record for autodiscover.<domain> to autodiscover.outlook.com as the setup specifies I should.  It pings correctly to Microsoft but doesn't respond to https (443).
3. Succeeded on autodiscover.<domain>.  Since I have the CNAME record, this works as I would expect.  Again, not sure why https isn't working on microsofts side.
4. Everything else after this worked except a warning with "Analyzing the certificate chains..."  But again, I would expect Microsoft to support their own software.  Might be an incorrect assumption but what else can I do about it?

So the end result is that it's successfully but there are a few potential issues in there.  Maybe the initial setup tries the first two and correctly moves on to the third before succeeding and works.  But then on subsequent connections, it for some reason expects one of the first two secure options to work and doesn't even try the non-secure third option.  I'm just guessing here.  I have no idea what it's doing.

Autodiscover should be properly configured, but it - as you mentions - works once and then fails after closing Outlook. I got the following RCA Test Results from https://testconnectivity.microsoft.com/?testid=O365Ola

(IN XML Format...)

<?xml version="1.0" encoding="utf-8"?>

<testresult status="Error" errorid="734044ef-11c2-4e30-9ee6-450d49e9d92c" contentUrl="" testdescription="Testing Outlook connectivity." resultdescription="The Outlook connectivity test failed." additionaldetails="" elapsedMilliseconds="3358">

  <children>

    <testresult status="SuccessWithWarnings" errorid="00000000-0000-0000-0000-000000000000" contentUrl="" testdescription="The Microsoft Connectivity Analyzer is attempting to test Autodiscover for ******@AllOEMs.com." resultdescription="Autodiscover was tested successfully." additionaldetails="" elapsedMilliseconds="3354">

      <children>

        <testresult status="SuccessWithWarnings" errorid="00000000-0000-0000-0000-000000000000" contentUrl="" testdescription="Attempting each method of contacting the Autodiscover service." resultdescription="The Autodiscover service was tested successfully." additionaldetails="" elapsedMilliseconds="3354">

          <children>

            <testresult status="SuccessWithWarnings" errorid="00000000-0000-0000-0000-000000000000" contentUrl="" testdescription="Attempting to test potential Autodiscover URL https://AllOEMs.com:443/Autodiscover/Autodiscover.xml" resultdescription="Testing of the Autodiscover URL was successful." additionaldetails="" elapsedMilliseconds="3354">

              <children>

                <testresult status="Success" errorid="00000000-0000-0000-0000-000000000000" contentUrl="" testdescription="Attempting to resolve the host name alloems.com in DNS." resultdescription="The host name resolved successfully." additionaldetails="IP addresses returned: 69.64.95.9" elapsedMilliseconds="1260">

                  <children />

                </testresult>

                <testresult status="Success" errorid="00000000-0000-0000-0000-000000000000" contentUrl="" testdescription="Testing TCP port 443 on host alloems.com to ensure it's listening and open." resultdescription="The port was opened successfully." additionaldetails="" elapsedMilliseconds="825">

                  <children />

                </testresult>

                <testresult status="SuccessWithWarnings" errorid="734044ef-11c2-4e30-9ee6-450d49e9d92c" contentUrl="" testdescription="Testing the SSL certificate to make sure it's valid." resultdescription="The certificate passed all validation requirements." additionaldetails="" elapsedMilliseconds="366">

                  <children>

                    <testresult status="Success" errorid="00000000-0000-0000-0000-000000000000" contentUrl="" testdescription="The Microsoft Connectivity Analyzer is attempting to obtain the SSL certificate from remote server alloems.com on port 443." resultdescription="The Microsoft Connectivity Analyzer successfully obtained the remote SSL certificate." additionaldetails="Remote Certificate Subject: CN=alloems.com, OU=PositiveSSL, OU=Domain Control Validated, Issuer: CN=COMODO RSA Domain Validation Secure Server CA, O=COMODO CA Limited, L=Salford, S=Greater Manchester, C=GB." elapsedMilliseconds="159">

                      <children />

                    </testresult>

                    <testresult status="Success" errorid="00000000-0000-0000-0000-000000000000" contentUrl="" testdescription="Validating the certificate name." resultdescription="The certificate name was validated successfully." additionaldetails="Host name alloems.com was found in the Certificate Subject Common name." elapsedMilliseconds="0">

                      <children />

                    </testresult>

                    <testresult status="SuccessWithWarnings" errorid="734044ef-11c2-4e30-9ee6-450d49e9d92c" contentUrl="" testdescription="Certificate trust is being validated." resultdescription="The certificate is trusted and all certificates are present in the chain." additionaldetails="">

                      <children>

                        <testresult status="Success" errorid="00000000-0000-0000-0000-000000000000" contentUrl="" testdescription="The Microsoft Connectivity Analyzer is attempting to build certificate chains for certificate CN=alloems.com, OU=PositiveSSL, OU=Domain Control Validated." resultdescription="One or more certificate chains were constructed successfully." additionaldetails="A total of 2 chains were built. The highest quality chain ends in root certificate CN=COMODO RSA Certification Authority, O=COMODO CA Limited, L=Salford, S=Greater Manchester, C=GB." elapsedMilliseconds="28">

                          <children />

                        </testresult>

                        <testresult status="Warning" errorid="1339c33a-8f21-427b-a323-4cee1a13f517" contentUrl="" testdescription="Analyzing the certificate chains for compatibility problems with versions of Windows." resultdescription="Potential compatibility problems were identified with some versions of Windows." additionaldetails="The Microsoft Connectivity Analyzer can only validate the certificate chain using the Root Certificate Update functionality from Windows Update. Your certificate may not be trusted on Windows if the "Update Root Certificates" feature isn't enabled." elapsedMilliseconds="5">

                          <children />

                        </testresult>

                      </children>

                    </testresult>

                    <testresult status="Success" errorid="00000000-0000-0000-0000-000000000000" contentUrl="" testdescription="Testing the certificate date to confirm the certificate is valid." resultdescription="Date validation passed. The certificate hasn't expired." additionaldetails="The certificate is valid. NotBefore = 7/31/2014 12:00:00 AM, NotAfter = 7/30/2019 11:59:59 PM" elapsedMilliseconds="0">

                      <children />

                    </testresult>

                  </children>

                </testresult>

                <testresult status="Success" errorid="00000000-0000-0000-0000-000000000000" contentUrl="" testdescription="Checking the IIS configuration for client certificate authentication." resultdescription="Client certificate authentication wasn't detected." additionaldetails="Accept/Require Client Certificates isn't configured." elapsedMilliseconds="305">

                  <children />

                </testresult>

                <testresult status="Success" errorid="00000000-0000-0000-0000-000000000000" contentUrl="" testdescription="Attempting to send an Autodiscover POST request to potential Autodiscover URLs." resultdescription="The Microsoft Connectivity Analyzer successfully retrieved Autodiscover settings by sending an Autodiscover POST." additionaldetails="" elapsedMilliseconds="595">

                  <children>

                    <testresult status="Success" errorid="00000000-0000-0000-0000-000000000000" contentUrl="" testdescription="The Microsoft Connectivity Analyzer is attempting to retrieve an XML Autodiscover response from URL https://AllOEMs.com:443/Autodiscover/Autodiscover.xml for user @AllOEMs.com." resultdescription="The Autodiscover XML response was successfully retrieved." additionaldetails="Autodiscover Account Settings XML response: <?xml version="1.0"?> <Autodiscover xmlns:xsd="http://www.w3.org/2001/XMLSchema" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xmlns="http://schemas.microsoft.com/exchange/autodiscover/responseschema/2006">  <Response xmlns="http://schemas.microsoft.com/exchange/autodiscover/outlook/responseschema/2006a">    <User>      <DisplayName>@alloems.com</DisplayName>    </User>    <Account>      <AccountType>email</AccountType>      <Action>settings</Action>      <Protocol>        <Type>IMAP</Type>        <Server>alloems.com</Server>        <Port>993</Port>        <DirectoryPort>0</DirectoryPort>        <ReferralPort>0</ReferralPort>        <SSL>on</SSL>        <DomainRequired>off</DomainRequired>        <SPA>off</SPA>        <AuthRequired>on</AuthRequired>        <LoginName>@alloems.com</LoginName>      </Protocol>      <Protocol>        <Type>SMTP</Type>        <Server>alloems.com</Server>        <Port>465</Port>        <DirectoryPort>0</DirectoryPort>        <ReferralPort>0</ReferralPort>        <SSL>on</SSL>        <DomainRequired>off</DomainRequired>        <SPA>off</SPA>        <AuthRequired>on</AuthRequired>        <LoginName>@alloems.com</LoginName>      </Protocol>    </Account>  </Response> </Autodiscover> HTTP Response Headers: Keep-Alive: timeout=5, max=100 Connection: Keep-Alive Content-Length: 1193 Content-Type: application/xml; charset="UTF-8" Date: Tue, 04 Aug 2015 17:58:31 GMT Server: Apache/2.2.29 (Unix) mod_ssl/2.2.29 OpenSSL/1.0.1e-fips mod_bwlimited/1.4 " elapsedMilliseconds="594">

                      <children />

                    </testresult>

                  </children>

                </testresult>

              </children>

            </testresult>

          </children>

        </testresult>

      </children>

    </testresult>

    <testresult status="Error" errorid="65e7befa-34fb-4039-9e2a-31e5fe2fcfe8" contentUrl="" testdescription="Autodiscover settings for Outlook connectivity are being validated." resultdescription="The Microsoft Connectivity Analyzer wasn't able to validate Outlook Autodiscover settings." additionaldetails="No account settings were returned from the Autodiscover response." elapsedMilliseconds="1">

      <children />

    </testresult>

  </children>

</testresult>

I'm guessing they only support RPC over HTTP, not MAPI over HTTP.   Set this key on your computer and see if Outlook finds the account -

HKEY_CURRENT_USER\Software\Microsoft\Exchange]

“MapiHttpDisabled”=dword:00000001

They are not using Office 365, but run their own Ex Server.  It appears they are using Exchange Server 2010.