Hub v2 flashing blue since yesterday

Any suggestions on how to get my hub back online?
I’ve tried many of the suggestions I have found on this forum.
Router is working.
Nothing but flashing blue on the hub.

Any helpful suggestions would be appreciated.

It would be helpful to know what you have done?

Unplug it from the power and remove the battery. Then plug them back in.

Seems to be back online now.
Not sure what fixed it.