If you frequently see "Sensor doesn't fit" message on GoBe's display, you can tighten the strap a little, to a comfortable position. The band’s sensor needs to stay in close contact with your skin, but it should not be so tight as to hurt your wrist.
Please also try cleaning the sensor of the device with alcohol wipes at least a few times a week, especially after any physical activity. To clean the sensor, you can use surfactant dishwashing liquid or liquid soap: apply a small amount of liquid on the sensor, rub it lightly (you can use a q-tip), then rinse with water and dry with a soft cloth or paper tissue.
You can also try wearing GoBe3 on another wrist to see if it makes any difference. Please note that any skin imperfections, such as scars, tattoos and even extensive hair growth can prevent GoBe from establishing proper contact with your skin.
We hope these recommendations are helpful! If you have any questions, please email us at firstname.lastname@example.org We will be happy to help!