Can`t send string via UDP

Good day. I am trying to send a JSON string through UDP.
For this, I made an item:

String udpBroadcast_25000 “Broadcast UDP JSON to port 25000 [% s]” (gNetwork) {udp = “> ['REGEX((.*)) ']”}

And the rule:

rule “Kitchen light manual control”
Item kitchenLight_brightness changed
var String json = '{
“deviceID”: “CC: 50: E3: 56: 2B: 38”,
“parameter”: “brightness”,
“value”: ‘+ kitchenLight_brightness.state.toString () +’
} ’
udpBroadcast_25000.sendCommand (json);

But when I try to send in the log, I get the message:

[WARN] [g.tcp.AbstractDatagramChannelBinding] - The channel for / has no connection pending (null)

Tell me, what is wrong here?

The problem seems to be that OH2 on the Raspberry PI3 cannot send to the broadcast address:

I get an error:
An exception occurred while connecting a channel: Permission denied

Maybe I should specify some more parameters? Or do something else?

At the same time, if you specify Unicast (, then the packets are sent normally …
The following question arose: is it possible in the expression

String udpBroadcast_25000 “Broadcast UDP JSON to port 25000 [% s]” (gNetwork) {udp = “> ['REGEX((.*)) ']”}

substitute IP address from item value?