This worked for me as well, with one extra step, I had to start setting up a new pairing before mine came back. Or I was just too impatient. I am connected again. Thank you Husqvarna.
I have the same issue, it would be great to only have the lights on in the real evening and night.
I am having the same issue for the first time today with my 450X. Before today I have not had any connection issues, the app was working perfectly. Since roughly 3:30 CDT today my app has just said "Disconnected". I also noticed that the mower screen has an "X" near what looks like a cell signal icon. Second icon after the GPS icon. This icon doesn't seem to be in the manual.
I did also try to turn the mower off, wait, and back on again multiple times. As well as rebooted my phone several times. No luck.