GoBe2 shuts down automatically after 5 minutes detecting no contact with the skin. Perhaps that's what was happening for you.
The sensor needs to stay in close contact with the skin, but it should not hurt your wrist. Other possible reasons for losing contact are skin imperfections, tattoos, scars, extensive hair growth, or excessive dryness of the skin. If any of these apply to you, you can try wearing GoBe2 on another arm or on the inside of your wrist and see if it helps.
If the problem persists, please email us at gobe@healbe.com, we will send you a test to perform to check if your device is defective.