Welcome @goksean , sorry to hear you are having issues.
I recently had a power outage like nothing I experienced before. It flickered about a dozen times before it went out basically causing my bulbs to go into pairing mode. In addition, my Hub was in the same state as yours.
The way I got mine back online was to remove the power from it then press and hold the button for about 10 Seconds, you should see the lights change, then I plugged the Power back in and went through the add device and it connected and worked fine. Did not remove the hub or do anything with my HMS, simply went through the Add Device process.
Here are some links:
Second Paragraph