Outlook App does not respect autodiscover.xml file to configure mailbox (iOS and Android)

Question

Both the Outlook App for iOS and Android don't seem to respect the /autodiscover.xml file that normally is used to provide the mail settings required for a given mail address.

I can not find any information about this anywhere online. I am sure things work perfectly when you want to autoconfigure an Exchange environment, but that is not what I am talking about here.

Our setup (that works correctly for the Outlook 365 desktop software):

1. We host a file on https://[domain]/autodiscover/autodiscover.xml

2. That content looks as follows:

   <?xml version="1.0" encoding="utf-8" ?>
   <Autodiscover xmlns="http://schemas.microsoft.com/exchange/autodiscover/responseschema/2006">
       <Response xmlns="http://schemas.microsoft.com/exchange/autodiscover/outlook/responseschema/2006a">
           <User><DisplayName></DisplayName></User>
           <Account>
               <AccountType>email</AccountType>
               <Action>settings</Action>
               <Protocol>
                   <Type>IMAP</Type>
                   <Server>mail.server.nl</Server>
                   <Port>993</Port>
                   <DomainRequired>off</DomainRequired>
                   <SPA>off</SPA>
                   <SSL>on</SSL>
                   <AuthRequired>on</AuthRequired>
                   <LoginName></LoginName>
               </Protocol>
               <Protocol>
                   <Type>POP3</Type>
                   <Server>mail.server.nl></Server>
                   <Port>995</Port>
                   <DomainRequired>off</DomainRequired>
                   <SPA>off</SPA>
                   <SSL>on</SSL>
                   <AuthRequired>on</AuthRequired>
                   <LoginName></LoginName>
               </Protocol>
               <Protocol>
                   <Type>SMTP</Type>
                   <Server>mail.server.nl></Server>
                   <Port>587</Port>
                   <DomainRequired>off</DomainRequired>
                   <SPA>off</SPA>
                   <Encryption>TLS</Encryption>
                   <AuthRequired>on</AuthRequired>
                   <LoginName></LoginName>
               </Protocol>
           </Account>
       </Response>
   </Autodiscover>
   

And after I configure info@[domain] I verified that this file is indeed accessed!

Notes:

• I also tried to set up SRV records. But also that had no effect.
• The tool that previously existed from Microsoft to test autodiscovery issues does no longer exist.

Anyone knows what is going on?