Rachio 3 offline

After swtched off during the winter, the controller was offline after switched on.
I tried to use my ipad to connet rachio, but failed.
I also tried to us PC connect bat, but cannot find Rachio on my PC.

Have you confirmed that you actually have power at the Rachio unit? Did you make any wifi router changes while the controller was switched off for the winter?

I have power at the Rachio unit, but I might made wifi router change.
When I tried to set up Rachio in my iphone setting, it was failed.