Acrobat Error: [strict] Ignoring policy file with incorrect syntax

[Richard5CBF]

The same crossdomain.xml file has been implemented for 3 endpoints (on 3 different domains / servers) to facilitate posting data from a PDF and getting an FDF response back.

The post from the PDF is working as expected to 2 of the 3 servers. But the third server is still triggering the yellow security alert pop up in Adobe Reader.

I can see the following entries in the cross domain log file for the third server:

Error: [strict] Ignoring policy file with incorrect syntax: https://exampledomain.net/crossdomain.xml

Error: Request for resource at https://exampledomain.net/api/v1/abc/xyz by requestor from http://* is denied due to lack of policy file permissions.

I see that the log is complaining about syntax but there are no differences between the crossdomain.xml file downloaded off the server that works and the one that is broken. The xml also validates and I am able to view the XML when I hit: https://exampledomain.net/crossdomain.xml

Here is the content of the crossdomain.xml file that I'm using:

<?xml version="1.0"?>
<!DOCTYPE cross-domain-policy SYSTEM "http://www.adobe.com/xml/dtds/cross-domain-policy.dtd">
<cross-domain-policy>
  <site-control permitted-cross-domain-policies="all"/>
  <allow-access-from domain="*" secure="false"/>
  <allow-http-request-headers-from domain="*" headers="*" secure="false"/>
</cross-domain-policy>

Please could you let me know what could be causing this problem on the third server? Thank you.

Additional detail - The server that is causing the problem is running IIS.

[hadisesancak]

https://exampledomain.net/crossdomain.xml your spi or web server which port accepting for connection ? 80 443 another. 
Sample https://localhosts.mobi/8080

A helpful video https://www.youtube.com/watch?v=_ufMfbRYB_8 

[Richard5CBF]

@hadisesancakThe server is using port 443 / SSL for connection.

Thanks for the video, but it doesn't address the issue I am facing at all.