UsbDiscoverer

Hello,

I have developed a test application for printing labels.
Sometimes it prints like a charm, sometimes it doesn't print anything and
just throws exceptions like "Malformed Multipart Form Data" and "Malformed status response - unable to determine printer status".
Can you please help me with these errors?
I am using the latest Zebra.SDK nuget package (2.15.2634), Firmware version is V84.20.22Z.

Here is my sample code:

Trying the Zebra.Printer.SDK in a .net framework 4.7 project it works fine with version 2.15.2634 but in a .net core 2.2 application using the .net standard 2.0 version of the nuget package no UsbDiscoverer is available.