Confirmed uplink with LoPy


In the scope of my master thesis I am implementing the loraserver-project.
I use a LAIRD RG1xx gateway and a lopy sensor node.
The current implementation is the combination of the Semtech forwarder on the GW and the LoRa-gateway-bridge.

I’m having trouble with sending confirmed uplink messages (unconfirmed is going perfectly).
When I do so, I can see that the lora-app-server responding with an unconfirmed downlink message which I receive in the logs of my gateway.
However, my sensor node doesn’t get the ACK.

I get the following error:
OSError: [Errno 11] EAGAIN
MicroPython v1.8.6-849-baa8c33 on 2018-01-29; LoPy with ESP32

The relevant code I use to send the message is:

s = socket.socket(socket.AF_LORA, socket.SOCK_RAW)
s.setsockopt(socket.SOL_LORA, socket.SO_DR, 5)
s.setsockopt(socket.SOL_LORA,socket.SO_CONFIRMED, 1)
count = s.send(str.encode(str(i)))

And it blocks on (probably a time out) of the s.send. Does it have to do with the understanding of the downlink message or is it maybe outside the receive windows?

If needed I can always provide more code/logs.

Thank you in advance.
Kind regards.

As a sidenote:

If I try Unconfirmed uplink (with adr=True) and print what has been received by the node I get b’’ back.
The code on the LoPy:
count = s.send(str.encode(str(i)))
data = s.recv(128)

Does this maybe indicate a possible wrong interpretation of the lora msg?