Created 8/31/2011
Last Reviewed 3/21/2016
Versions 6.1, 7.0


When you try to view a presentation that uses a Silverlight player, the following error appears:

Unable to play the presentation. The media server may not be available or the media stream format may not be supported. (4001 An error has occurred.)


Proxy Server

This error can occur when you go through an authenticated proxy in order to get to the internet. Silverlight does not currently provide a means to authenticate with a proxy server. In order to use the Silverlight-based players, you must add an exception for the Mediasite server to the proxy server, or the proxy server entirely. Please contact your organization's IT staff for assistance with proxy server settings. If the proxy server cannot be bypassed, then the classic HTML-based Mediasite players can be used to view presentations. This is an option that needs to be set up on the Mediasite server, so contact your local Mediasite administrator to inquire about this option. Note that playback would only work in Internet Explorer in this case, as all other browsers use Silverlight for video playback when using an HTML player.


There is also an issue specific to Firefox where this error can occur under certain conditions. If you experience this issue when using Firefox, but not when using Internet Explorer, then try this:

  1. Go to Start > Control Panel > Internet Options.
  2. Click the Connections tab, and then the LAN Settings button at the bottom.
  3. Clear the box labeled "Automatically detect settings."
  4. Click OK, then Apply and OK.


EX Server

There are also other issues on the Mediasite EX Server that can cause the 4001 error. If you do not go through a proxy server to access the internet, please contact your Mediasite server administrator for assistance.


Additional Comments

For more information about possible causes for this error on the server please see KBA3111.


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