SharePoint 2013 office web app error - Unable to open document

Hello All, 

I have setup SharePoint 2013 and Office Web Apps Server 2013 which meet all the system requirements. I have setup the OWA server to allow for HTTP in my test environment. 

When I try to open any document I get the below error message 

Sorry, there was a problem and we can’t open this document. If this happens again, try opening the document in Microsoft Word

I have my SharePoint site created on http without a host header. My SP site url is http://servername:portnumber

I also checked the article 

http://social.msdn.microsoft.com/Forums/en-US/sharepointgeneral/thread/f7be5f88-8c98-464e-8596-60956b5e98fd but it did not help.