Error Loading WSDL

Sometimes in SoapUI I get the below error while sometimes it just load the wsdl:

There was something wrong with the WSDL you are trying to import

Error loading [http://wcf-int.eolintra.emirates.com/flightstatus.svc?wsdl]: org.apache.xmlbeans.XmlException: org.apache.xmlbeans.XmlException: error: Unexpected end of file after null