2021-10-17 16:36:53:962 [Instrumentation] Caused by: java.lang.IllegalStateException: UiAutomationService android.accessibilityservice.IAccessibilityServiceClient$Stub$Proxy@63c31ebalready registered!
2021-10-17 16:36:53:962 [Instrumentation]     at android.os.Parcel.createException(Parcel.java:1958)
2021-10-17 16:36:53:962 [Instrumentation]     at android.os.Parcel.readException(Parcel.java:1918)
2021-10-17 16:36:53:962 [Instrumentation]     at android.os.Parcel.readException(Parcel.java:1868)
2021-10-17 16:36:53:962 [Instrumentation]     at android.app.IUiAutomationConnection$Stub$Proxy.connect(IUiAutomationConnection.java:255)
2021-10-17 16:36:53:963 [Instrumentation]     at android.app.UiAutomation.connect(UiAutomation.java:234)
2021-10-17 16:36:53:963 [Instrumentation]     at android.app.Instrumentation.getUiAutomation(Instrumentation.java:2145)
2021-10-17 16:36:53:963 [Instrumentation]     at androidx.test.uiautomator.UiDevice.getUiAutomation(UiDevice.java:1129)
2021-10-17 16:36:53:963 [Instrumentation]     at androidx.test.uiautomator.QueryController.<init>(QueryController.java:95)
2021-10-17 16:36:53:963 [Instrumentation]     at androidx.test.uiautomator.UiDevice.<init>(UiDevice.java:109)
2021-10-17 16:36:53:963 [Instrumentation]     at androidx.test.uiautomator.UiDevice.getInstance(UiDevice.java:261)
2021-10-17 16:36:53:963 [Instrumentation]     at io.appium.uiautomator2.utils.Device.getUiDevice(Device.java:33)
2021-10-17 16:36:53:964 [Instrumentation]     at io.appium.uiautomator2.model.internal.CustomUiDevice.<init>(CustomUiDevice.java:70)
2021-10-17 16:36:53:964 [Instrumentation]     at io.appium.uiautomator2.model.internal.CustomUiDevice.getInstance(CustomUiDevice.java:80)
2021-10-17 16:36:53:964 [Instrumentation]     at io.appium.uiautomator2.server.mjpeg.MjpegScreenshotStream.<clinit>(MjpegScreenshotStream.java:43)
2021-10-17 16:36:53:964 [Instrumentation]     ... 32 more
2021-10-17 16:36:54:032 [Instrumentation] INSTRUMENTATION_RESULT: shortMsg=Process crashed.
2021-10-17 16:36:

Through the error information search of caused by, we know that because the uiautomator process already exists, we need to kill the process first

Solution 1:
1. Query ADB process:

adb shell ps | find "uiautomator"

2. Kill process:

adb shell kill <PID>

3. If you are prompted with “/ system/bin/sh: Kill: 1835: operation not permitted”, you need to switch ADB to root permission and kill the process

adb root

Solution 2:

Restart the phone