RG191 stop connection to TTN

Over the last few weeks, one of my RG191 would just stop passing traffic to TTN
it’s now happen 6 times or more…

TTN Console say it not connected
RG191 say it’s connected to TTN
RG191 is receiving traffic from my devices
Rebooting will re-establish a connection to TTN

Laird Linux gatwick-laird-93.8.5.21

Just now turned on loggings in the RG191