Error: "OTA version is not compatible" when running the Agility/Quality Center integration

This feature is available in all editions

Problem

After attempting to run the Agility/Quality Center integration, there is an "OTA version is not compatible" error.

After upgrading a Quality Center instance or after using a browser (Internet Explorer) that was previously used to open an older version of Quality Center, you might experience a class of errors that are related to the incorrect OTA when running the integration with a newer instance.

OTA refers to the Quality Center API (Open Test Architecture). When you browse to your Quality Center instance for the first time, some dlls are downloaded to location Program file > Common Files > Mercury Interactive > Quality Center. After executing the Agility.Servicehost.exe, the process loads the OTA dll and makes an attempt to connect to Quality Center but throws an exception because the OTA is out of date.

The console errors look similar to this:

Failed to execute QualityCenter connection validation

System.Runtime.InteropServices.COMException (0x80047535): OTA version is not compatible
  with the Application Lifecycle Management server

Solution

Refresh the OTA libraries:

1. Open a browser and go to Quality Center on the machine where you are trying to run the integration
2. If you have a URL like http://hpmercury10:8080/qcbin/start_a.htm to access Quality Center, cut off the start_a.htm to get to the screen that you need
3. Click Add-Ins Page
4. Then click HP Quality Center Connectivity to install.
5. Rerun integration