Please refer to the following steps to troubleshoot the issue:
1. The reason why the band cannot be turned on is that it is out of power. The band cannot be charged because the charging contacts are oxidized. You can try to clean the charging contacts to see if it can be charged;
2. Try to plug and unplug the charging cable 5 times in a row to force recovery;
3. Next, make sure that the USB port (PC or other power supply device) is powered normally, and try to change the USB charging cable of the band. Or try to change the USB port of the power supply device.