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>