Does anyone have some advice on how to sort out a sensor calibration issue.

  

Firmware is up to date on all devices.

  

Unable to do the calibration with the DJI calibration board and DJI assistant 2.

  

DJI Go App Keeps issuing warnings.

Please see screen shots attached below.

  

Any tips or advice would be much appreciated, thanks in advance.

Have you done a calibration before? Its not as intuitive as the manual says i followed the Assistant 2 and just couldn't get 100% . There is a Youtube video showing how to do it correctly watch that and you will find it easy after that  

The DJI Assistant 2 program can not tolerate multiple monitors, single monitor must be in landscape and cannot be greater that 1600 x 900. If any of these are configured, then change your display configuration.

Also, for calibration, the Vision driver must load when the aircraft is connected to the USB.

(On a PC, it's the libusb-win32 devices entry in Device Manager with the subkey Vision (Interface 3). Look at it's properties and ensure the device status is "working properly". If it states otherwise, then run the Installer_x64 or Installer_x86 (located in C:\Program Files (x86)\DJI Product\DJI Assistant 2\Drivers\Vision) as appropriate for your system and then reboot everything and try again.)

If the calibration keeps failing, have you tried using a different monitor if possible?

At first I tried to manage the DJI assistant 2 on my PC and still had no luck. I then used a Apple Macbook with Assistant 2 and was successful to proceed with the calibration process. However once the calibration process was complete and i restarted my inspire 2, I am still getting warning messages on the ipad as seen in the screen shot.  

Desert Drone Pi Posted at 2017-3-21 01:26
At first I tried to manage the DJI assistant 2 on my PC and still had no luck. I then used a Apple Macbook with Assistant 2 and was successful to proceed with the calibration process. However once the calibration process was complete and i restarted my inspire 2, I am still getting warning messages on the ipad as seen in the screen shot.

Have you tried restoring to factory defaults in the Assistant 2, along with an IMU calibration after the sensor calibration?