I can't find anyone else who has mentioned this particular error code with a similar situation. 

 My slingbox classic has worked fine for a few years, both inside the network and from all places from a hotel to a Verizon wireless card.  However, we have recently set up an enitre new server at our office. 

Sling works from home. 

Sling works from public wifi and our office neighbors unsecured wifi connection.

Sling does not work from our work network.  I get this error (0x8007274d) at work.  My IT guy says he would be happy to open whatever hole is needed for the slingplayer but does not know what that particular error refers to.  We are using fairly standard firewall equiptment, have a fine connection and I am hitting through my home router from other outside points.

 Anyone have an advice?