Vuforia image-target crashing Hololens MRTK

I'm using vuforia to create a 3D popup/interactable gameobject using Unity 2019.2.8f1 for the Hololens 1 (MRTK package: Microsoft.MixedReality.Toolkit.Unity.Foundation.2.2.0). I am trying to get a slider (from MRTK) to popup when the hololens looks at a QR code in the real world. I've followed the instructions/guidance as per: Setting up Hololens MRTK 2.0 with Vuforia in Unity 2019.1 & https://www.youtube.com/watch?v=MtiUx_szKbI&t=716s. When simulating the application in Unity, i.e. hitting the play button, the application works fine (it's slightly jittery - but that's just vuforia). When I build and deploy to the Hololens however, I get a kernelbase.pdb not loaded error.

More specifically, the error is as follows:

Exception thrown at 0x76FC3072 in ArmillarySphere.exe: Microsoft C++ exception: Platform::AccessDeniedException ^ at memory location 0x15DFFAF0. HRESULT:0x80070005 Access is denied. WinRT information: A network capability is required to access this network resource

This is perplexing as I'm deploying my application to the Hololens via a USB cable - and this method of deployment works for everything until I start to incorporate vuforia.

Has anyone got any idea why this exception is being thrown (or at least point me in the right direction)?

Thanks in advance!