Following RMCA Autodiscover POST Request, Retrieval of autodiscover XML Response fails

Question

Hello,

Givens:

• Network Test: ok (all green)
• Outbound SMTP Email test: ok (all green)
• Inbound SMTP Email test: ok (all green)
• Outlook Connectivity test: partially ok. The following error is displayed at the stage of "Attempting to contact the Autodiscover service using the DNS SRV redirect method", specifically to retrieve the autodiscover XML response to the POST reques:


Attempting to contact the Autodiscover service using the DNS SRV redirect method.
The Microsoft Connectivity Analyzer failed to contact the Autodiscover service using the DNS SRV redirect method.
Test Steps

Attempting to locate SRV record _autodiscover._tcp.domain.de in DNS.
The Autodiscover SRV record was successfully retrieved from DNS.
Additional Details
The Service Location (SRV) record lookup returned host mail.domain.de.

Attempting to test potential Autodiscover URL https://mail.domain.de:443/Autodiscover/Autodiscover.xml
Testing of this potential Autodiscover URL failed.
Test Steps

Attempting to resolve the host name mail.domain.de in DNS.
The host name resolved successfully.
Additional Details

Testing TCP port 443 on host mail.domain.de to ensure it's listening and open.
The port was opened successfully.

Testing the SSL certificate to make sure it's valid.
The certificate passed all validation requirements.
Test Steps


Attempting to send an Autodiscover POST request to potential Autodiscover URLs.
Autodiscover settings weren't obtained when the Autodiscover POST request was sent.
Test Steps

The Microsoft Connectivity Analyzer is attempting to retrieve an XML Autodiscover response from URL https://mail.domain.de:443/Autodiscover/Autodiscover.xml for user user1@domain.de.
The Microsoft Connectivity Analyzer failed to obtain an Autodiscover XML response.
Additional Details
The Autodiscover XML response received by the Microsoft Connectivity Analyzer was invalid. Exception: Exception details:

Message: There is an error in XML document (1, 1).

Type: System.InvalidOperationException

Stack trace:

   at System.Xml.Serialization.XmlSerializer.Deserialize(XmlReader xmlReader, String encodingStyle, XmlDeserializationEvents events)

   at Microsoft.M365.RCA.ConnectivityTests.AutoDiscover.AutoDiscoverGetXMLBase`2.Discover()



Exception details:

Message: Data at the root level is invalid. Line 1, position 1.

Type: System.Xml.XmlException

Stack trace:

   at System.Xml.XmlTextReaderImpl.Throw(Exception e)

   at System.Xml.XmlTextReaderImpl.ParseRootLevelWhitespace()

   at System.Xml.XmlTextReaderImpl.ParseDocumentContent()

   at System.Xml.XmlReader.MoveToContent()

   at Microsoft.Xml.Serialization.GeneratedAssembly.XmlSerializationReaderOutlookAutoDiscoverResponseXML.Read11_Autodiscover()



HTTP Response Headers:

Connection: keep-alive

Vary: Accept-Encoding

Pragma: no-cache

X-Frame-Options: SAMEORIGIN

X-XSS-Protection: 1; mode=block

X-Content-Type-Options: nosniff

Strict-Transport-Security: max-age=31536000

Content-Security-Policy: default-src 'self'; script-src 'self' 'unsafe-eval' 'unsafe-inline'; style-src 'self' 'unsafe-inline'; img-src 'self' data:; connect-src 'self' wss:; font-src 'self'; object-src 'self'; media-src 'self'; child-src 'self'

X-Content-Security-Policy: default-src 'self'; script-src 'self' 'unsafe-eval' 'unsafe-inline'; style-src 'self' 'unsafe-inline'; img-src 'self' data:; connect-src 'self' wss:; font-src 'self'; object-src 'self'; media-src 'self'; child-src 'self'

X-Webkit-CSP: default-src 'self'; script-src 'self' 'unsafe-eval' 'unsafe-inline'; style-src 'self' 'unsafe-inline'; img-src 'self' data:; connect-src 'self' wss:; font-src 'self'; object-src 'self'; media-src 'self'; child-src 'self'

Content-Length: 116

Cache-Control: no-cache

Cache-Control: must-revalidate

Content-Type: text/html;charset=utf-8

Date: Fri, 24 Mar 2023 00:55:19 GMT

Expires: Sun, 28 Jan 2007 00:00:00 GMT

Location: https://mylocserv2ex19.domain.de/

Set-Cookie: wg_portald_session_id=b42faeaee5775839b39c7d63298fca335eff9cbc; expires=Fri, 24 Mar 2023 01:00:19 GMT; httponly; Path=/; secure

Server: none

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Apparently the testing tool sends a POST request to the Autodiscover URLs but does not get the autodiscover XML response. the error listing indicates a "Data at the root level is invalid" error!

The error details above are not understandable to me and I don't know what the next step to fix the error should be. The result Outlook Client cannot communicate with the Exchange server.

Can any one help with this problem?
Thanks
Thanks

Answer 1

Hi @KF ,

Just wondering is it causing real problems like users failed to connect to Outlook desktop clients or mobile devices?
Is it a suddenly occurred issue?

Additional Details The Autodiscover XML response received by the Microsoft Connectivity Analyzer was invalid. Exception: Exception details: Message: There is an error in XML document (1, 1).

This is really an odd error. I tried searching a lot but can hardly find anything that applies to it either. Below is a thread which contains a similar error, and according to the sharing at the very end, the issue was finally found to be due to the http redirect configured on the load balancer. So maybe you can also check it from your end if you have similar settings implemented.
Autodiscover Failure in exchange 2010 sp3
(Please Note: Since the web site is not hosted by Microsoft, the link may change without notice. Microsoft does not guarantee the accuracy of this information.)

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