This QVP protocol indicates that the customer is using IE-plugin (or Desktop) client. qvp://
This part indicates that the customer is using IIS as QlikView webserver iis_authenticate=
This part indicates that tunneling is failing tunneler=
So, the customer is using IE-plugin (or Desktop) client and get this error. The root cause is port 4747 (required for IE-plugin/Desktop) is blocked at the time for some reason. When QlikView finds port 4747 is blocked, it's trying to use "tunneling" and use port 80. However, if the tunneling is not setup correctly in IIS, then the tunneling will fail. That is what's happening.
Verify tunneling is working : http://’servername’/scripts/qvstunnel.dll?test => You should get a response like
Common solutions are as below:
Internet Explorer Compatibility Settings are not compliant with QlikView requirements