1) Check if the device has any battery drain issues. When the device consumes battery too fast, it results in slow charging.
2) Verify whether there are any third-party power management software apps downloaded. If so, please uninstall these.
3) Only use the official charger to charge your device.
4) Please don't use the device for a long time while it is charging.
5) Please back up your personal data, then reset or update your device to the latest system version and try again.
If the problem persists, back up your data and take your device and proof of purchase to one of our repair centers to get more professional technical assistance.