First, you should be using the fully-qualified domain name, e.g. mmstest.be-intuitive.com (not mms.be-intuitive.local).
Second, use telnet to confirm you can access the site on HTTP port 80 and HTTPS port 443:
telnet yourserver.yourdomain.com 80
telnet yourserver.yourdomain.com 443
Both should connect and have a blinking _ at the command prompt, indicating that you can resolve yourserver.yourdomain.com and also reach it on the provided ports.
Finally, when you access the URL, it should say <result>success</result>, the URL being http://yourserver.yourdomain.com/MobileEnrollment/Symc-iOSEnroll.aspx
In all cases above, yourserver.yourdomain.com is not your NS but rather your MMS site server. If you cannot reach the server on port 80 or 443, it could be a network, DNS, or firewall issue. It could also be a failure for IIS to have a binding on the default site for the proper port.
If the .aspx fails, it could be failure to install .NET.
Does this help? If you still have an issue, please do post screenshots.