Downlink use only FPort:0 and no payload on packet

I’m using simple way to create downlink message from Server to node. Node is working class A.

  • by UI use base64 some payload and some ports( not zero). Enqueue payload and after uplink can see downlink, but FPort each just 0 : “FPort:0”

My node received message, recognized it correctly - But no any my payload presented?.
I’ve used different payload (few symbols, many symbols) - but sent package each time the same long (differently encoded) and in node receiving fully correct. And resutls the same - Header, MIC all recognied – but no payload. Can somebody help me – I really stack…

I’ve used API for different way to enqueue downlink corresponding examples:
{“devEUI”: “2022000002000021”,
“confirmed”: false,
“data”: “d6VaiAD/mSE=”,
“fPort”: 4
It’s enqueued correctly but after uplink message corresponding downlink still using FPort:0 and not placed any payload.

ANd node receiving message, MIC and other part all
I really need HELP, Please, somebody can say where I should see – I’ve check configuration files and not anything…
Absolutely strange situation…
Any idea, PLEASE

Downlink with fPort: 0 and a frmPayload means that the NS is sending mac-commands to the device. There is nothing wrong with, as mac-commands get priority over application payloads. It means that your application-payload (downlink) stays in the queue until the next downlink (if there are no more mac-commands that the NS needs to send).

Dear Brocaar, thanks a lot for your answer, but my problem exactly about that - I have queue loaded with my message and I can see that this framenumber is updating for next each time after uplink and downlink, but neve that message passed out – and I don’t understand. FCnt continue increasing on that page… and never gone out…

Really it looks as each time for uplink Chirpstack organizing downlink with Fport:0 and message still in queue. Also if queue is empty - still continued to send those MAC commands in answer to each uplink. Where that answer programmed ? I’ve check all configurations and cannot find any about that.