I have the same problem over here.
I've mounted the Wisnode Lora on top of an Arduino UNO.
Because my Wisnode was not delivered with the 'Shift board', I've made a voltage divider for the UNO-TX to bring it's output down to 3.3V (TX->10Kohm->RX wisnode, 20Kohm to Earth)
When I run the testprograms, I let my logic-analyzer look along at the signals, while also looking at the UART-tool directly on the COM of the Wisnode, and I look at the Arduino Serial Monitor.
When I reset the wisnode, I see the 'Welcome to RAK811' in the arduino serial monitor and the UART monitor. The arduino receives the serial information just fine.
When I send a command through the UART tool, I see the 'OK' confirmation in the serial monitor, so that's also fine.
But whatever I try to send, from the arduino, is completely ignored by the Wisnode.
I see on the logic analyzer that the data is sent to the RX pin on the Wisnode, I've confirmed that it is in the correct baudrate etc.
If necessary I can provide pictures /sourcecode of how I set things up as well..
I've been playing for hours now, but I am completely stuck on this, please help!