actual configuration: T-Impulse S76G K151 + LoRaWAN RAK Gateway + Chirpstack
I'm using the T-Impulse-S76G-LoRaWAN project with PlatformIO, I configured AppKey and DevEUI correctly.
The T-Impulse OLED is stuck on: "OTAA Joinin"

Serial log:
645196: EV_JOINING: -> Joining...
646119: Unknown event

On my network server, I detect the "JoinRequest" but the device is stuck in joining state (never joins the network).

What can I do to do some debugging?