To assess your stress level, the stress module needs information about your heart rate for the past hour. As long as these data are missing, the stress module stays in the calibration mode.
The stress algorithm works in a way that if you take off the band or if it loses contact with your skin for a relatively short period of time (up to 15 minutes), the algorithm will resume working from the last place. If, however, the band has been taken off or skin contact lost for more than 15 minutes, the calibration will start from scratch and it may take an hour or more for the band to collect all the necessary data to estimate the stress level.
If it's been more than a few hours in calibration mode for you, the process has probably been stuck. Please email us at gobe@healbe.com and send us a screenshot of the stress screen from the HEALBE app. Also, please let us know what stress data if any you see on the band's screen.