automx2 - error autodiscover with outlook client

[Eric DUVAL]

Hello,

automx2 installed on ubuntu xenial (16.04.6 LTS)
python 3.8.2
haproxy --> proxy apache2 --> automx2
MUA : outlook pro 2016

automx2 --> autoconfig OK
automx2 --> autodiscover KO

autodiscover:

Step 1 outlook: Create new account -> I enter the email address then I 
click on connection -> automx2 receives a first request GET 
"/autodiscover/autodiscover.json"

Details of the request:
"GET /autodiscover/autodiscover.json?Email=user at domain.tld& 
Protocol=ActiveSync&RedirectCount=1 HTTP/1.1" 404

Step 2 outlook: The advanced configuration is displayed, whatever my 
choice (Exchange or Exchange 2013 or earlier) the request received by 
automx2 is: /autodiscover/autodiscover.xml

Details of the request:
"POST /autodiscover/autodiscover.xml HTTP/1.1" 200

Step 3 outlook: Displays an error message (Outlook could not configure 
your account)


I did a connectivity test on https://testconnectivity.microsoft.com

The XML autodiscover response received by Microsoft's connectivity 
analyzer is not correct. The Exception Details exception:
Message : There is an error in XML document (1, 2).
Type : System.InvalidOperationException
Procedure call tree :
  at System.Xml.Serialization.XmlSerializer.Deserialize(XmlReader 
xmlReader, String encodingStyle, XmlDeserializationEvents events)
  at 
Microsoft.Exchange.Tools.ExRca.Tests.AutoDiscover.AutoDiscoverGetXMLBase`2.Discover()

Exception details:
Message : <Autodiscover 
xmlns='http://schemas.microsoft.com/exchange/autodiscover/outlook/requestschema/2006'> 
was not expected.
Type : System.InvalidOperationException
Procedure call tree :
  at 
Microsoft.Xml.Serialization.GeneratedAssembly.XmlSerializationReaderOutlookAutoDiscoverResponseXML.Read11_Autodiscover() 
has been met.


I don't understand the problem, Do you have an idea?

Regards
Eric