1. The contact on the smart device or charging cable is dirty.
Over time, dust and debris can build up and get in the way of charging.
2. The USB port or socket is faulty.
If you have not already done so, try a different port. The same effect can be achieved with UL certified wall chargers. Do not use a USB hub.
3, the smart device is not firmly connected to the charging cable.
Check the alignment and try to reconnect the smart device to the charging cable. Illustrations and tips on how to know if a connection is secure
4. The smart device fails.
When in doubt, turn your smart device off and restart it. For instructions,
The smart device got wet. Dry your smart device thoroughly before charging it