XSP4 localhost doesn't respond (Windows 8.1)

I have installed Mono 4.0.2 under Windows 8.1 64bit

Now I'm testing how it runs: everything is ok with console and WF applications

However, I can't run any ASP.NET app/page. I tried my own web apps and the simple example from there, the result is the same:

xsp4 starts, listening on port 9000, shows root directory (webapp directory) and waits.
I try to access localhost:9000/, localhost:9000/hello.aspx
Browser keeps waiting for response forever, nothing happens in console (I tried --verbose and --loginfo).

I tried different ports and both mono.exe and xsp4.exe are in firewall exception list. IPv6 is disabled. Test-NetConnection succeeds, but telnet doesn't go further than "Connecting To 127.0.0.1..."

How do I make it work properly?

Here is that page that I'm trying to access for test:

<%@ Page Language="C#" %>
<html>
<head>
   <title>Sample Calendar</title>
</head>
<asp:calendar showtitle="true" runat="server">
</asp:calendar>

netstat output:

#just launched xsp4. 2772 is mono.exe
PS C:\Users\Orif> netstat -aon | findstr 9000
  TCP    0.0.0.0:9000           0.0.0.0:0              LISTENING       2772

#now tried to access a page through firefox (5008)
PS C:\Users\Orif> netstat -aon | findstr 9000
  TCP    0.0.0.0:9000           0.0.0.0:0              LISTENING       2772

  TCP    127.0.0.1:2199         127.0.0.1:9000         ESTABLISHED     5008

  TCP    127.0.0.1:9000         127.0.0.1:2199         ESTABLISHED     2772

UPDATE

I've installed Xamarin Studio which has own copy of xsp4. That copy works perfectly fine.

Solution

It is still unclear what was causing the issue. Maybe it were system updates, or indeed it was a bug, but I've just installed Mono 4.4 and the issue is gone.