If it is the first time you use the device, make sure you removed the plastic protection from the sensor, it is not always visible at first glance.
Check that your charger is properly connected to a power supply. Ensure that the bracelet is correctly positioned on the charging station; with IP33 and IP67 chargers you should hear a "click"-sound and feel the magnetic attraction; If you think a force repulsing the bracelet, try rotating it by 180°. With the IP68 version either sides will work for charging.
You can try to connect the charger to a different USB port as for example the USB port of a Personal Computer.
If you have a charger with an exchangeable cable, you can try to use the cable of the cuff and plug it into the charger, to see if the problem is the cable.
Try pressing the bracelet against the charger with the thumb. If the led lights up when pressing against the charger, there might be a misconnection.
Please clean the charging station pins with a moistened tissue with alcohol and try again.
If it still does not charge and there is no red light glowing, please follow the troubleshooting steps through our support bot on the right bottom of the following page Aktiia FAQ You will be asked to provide videos or photos and other details that can help us identifying the issue quickly. At the end of the conversation, a Ticket with all information will be sent to our Customer support Team to assist you with your issue.