RFD 868 UX modem doesn't connect when POWER TX is set to lower than 30 value

Hi I am trying to connect RFD 868X modem to 868 UX modem. Connection is only enstablished if TX Power in 868 UX is set to 30 if it’s 27 connection doesn’t work. All other settings are the same. I have the newest firmware 3.15 in all modems. I have two 868 UX modems and the problems occurs on both modems. Any idea how to change TX POWER to lower value on 868 UX and get the connection ? Sometimes it’s working but usually no.

Are you using the RFD tool to set them? or in the MissionPlanner SiK radio screen?
I prefer the RFD tools since some of the settings are a little different compared to MP.
Just thought, not saying it’s a definite fix…

Thanks I am using RFD Tool. Last night I did general update in 4 modems to 3.20 firmware and set new parameters: 2 channels, AES encription, and it started to work in all modems I will check for how long. I have another problem RFD related but I have to investigate it further.