To save battery life I disconnected my Epson PULSENSE watch from my phone for a few days. When I tried to reconnect, I always got the error 20-0101-0008. But finally I managed to do it, here is the trick; disconnect completely:

  1. Tell your watch to deactivate bluetooth
  2. deactivate the connection in the iOS App
  3. tell iOS to ignore the watch in the bluetooth settings!

Lastly, reconnect via the Pulsense App. Now everything should run smoothly.