Please check whether the data cable, charger and socket are damaged or abnormal noise, if damaged, please replace.
4. It is recommended that you replace other chargers that can charge normally and try to charge.
If the charger can be charged normally after replacement, it may be the charger and data cable fault, if it can not be charged, it may be the phone itself.
It is recommended to bring the mobile phone, charger and data cable to the nearby customer service center for repair.
Initial suspicion is a systemic problem. You can check the version update in the Settings - My Settings -MIUI version, if there is a version that can be upgraded, upgrade the version, and restart may solve the problem.
If you upgrade to the latest version and still can't fix the problem, it needs to be repaired. If within the warranty period, you can go to the Xiaomi after-sales service center for testing, free wechat.