An unexpected error has occurred - controller offline

Hello Rachio Support
My controller RACHIO 3 went offline yesterday and I did every single thing and couldn’t able to bring it online. I reset the wifi and tried using my MacBook to bring it offline based on your instructions. It is currently stuck on white blinking with one time red 2nd quadrant. I have used all sorts of devices to make it work. I tried iPad 11 pro, iPad gen 7 IOS13.x, I tried iPhone XR ios 14.01. I tried MacBook pro 2016 10.15.6 (Catalina).
Please let me know what else should I do to make this work.

This happened 6 months ago as well.

All other devices in my home network works flawlessly. I have Linksys Velop mesh with full coverage.