Disconnected from Lexus App

[BGM]

Hi all, first time posting & very new member…please go easy on me. 
My wife and I, both in our mid 60s picked up our LBX prem Plus yesterday. 
love the look and the drive, too many beeps & bongs for me, but it’s ostensibly the wifes car. I digress. 
This evening whilst sat at home my wife received a message on her apple watch that she’s been disconnected from her Lexus app. We can’t seem to reconnect by either entering the RegNos or using QR code on veh display. The app is saying it doesn't recognise the RegNos and the dash message is saying that there’s no network connection and to contact dealership. 

I admit to being a luddite, but am I doing something wrong, or is their a known “fault” with the app?

Thanking everyone in anticipation.