Multicast downlink Data Rate config


I have created a Multicast group with several devices and I am trying to receive a multicast downlink.

I was able to receive by unicast, but I had problems with Multicast message due to Data Rate mismatch.

In the loraserver.toml I had rx2_dr = -1 by default and in the Multicast group configuration I had it set to 0 (configured On lora server UI).
Under this config the Multicast could not be rececived by the end-device.

Once I set the rx2_dr = 0 the multicast message could be received by the end-device, which is great.

If I set the Multicast Data Rate to -1 (configured On lora server UI) the value is not set and gives the following error:
“json: cannot unmarshal number -1 into Go value of type uint32 (code: 3)”

My question: Why cannot I set the Multicast Data Rate to -1 just as the default config. on the loraserver.toml so both parameters are the same?

Regards, Ramon.