when I use UnityWebRequest "Get" in Android(not only Android 9), I get unknow error and code 0,when I use UnityWebRequest "Get" in Android(not only Android9), I get unknow error and code is 0

when I use UnityWebRequest "Get" in Android(not only Android 9), I get unknow error and code 0,but when I use UnityEditor,I can get data,when I use UnityWebRequest "Get" in Android(not only Android9), I get "unknow error" and code is 0,but when I use UnityEditor,I can get data