You will just have to do it again. You don’t have to wait many hours for the slow breathing.
Read the extensive thread from the one below:
notilas Dec '19
I just figure it out, WD’s documentation is very confusing.
If the box still blink after 1 minute, the reset has failed, you need to do it agin.
press rest button with pin for 60 seconds, but the LED will NOT blink, however, stop pressing the button
After 5-10 seconds the mycloud will turn off by itself and start reboot
After reboot, LED will start blinking for 2-3 minutes, then it will reboot again