This is worth a try, if you are still stuck.
Disconnect hub from power. Press and hold the B button while re-connecting power to the hub. After a couple seconds of power, release the button.
The light may continue to flash yellow, give it a minute. Then remove from power and plug back in. Give it a minute or two, press the B button five times to go back to pairing mode.
Make sure you have removed the hub from your account before trying to add it back in.