MKRZero Connection Error. (Com opened, but upload error)

I used MKRZERO. In computer device management com 14 is founded, but in arduino the program is uploaded error. I don't know why lead to th phenomenon. The questions are as follows:
I had selected COM and MKRZero in Project.

项目使用了 15520 字节,占用了 (5%) 程序存储空间。最大为 262144 字节。
processing.app.debug.RunnerException
at cc.arduino.packages.uploaders.SerialUploader.uploadUsingPreferences(SerialUploader.java:152)
at cc.arduino.UploaderUtils.upload(UploaderUtils.java:77)
at processing.app.SketchController.upload(SketchController.java:732)
at processing.app.SketchController.exportApplet(SketchController.java:703)
at processing.app.Editor$UploadHandler.run(Editor.java:2070)
at java.lang.Thread.run(Thread.java:748)
Caused by: processing.app.SerialException: 接触串口 'COM14' 释出错。
at processing.app.Serial.touchForCDCReset(Serial.java:107)
at cc.arduino.packages.uploaders.SerialUploader.uploadUsingPreferences(SerialUploader.java:136)
... 5 more
Caused by: jssc.SerialPortException: Port name - COM14; Method name - openPort(); Exception type - Port busy.
at jssc.SerialPort.openPort(SerialPort.java:164)
at processing.app.Serial.touchForCDCReset(Serial.java:101)
... 6 more
No device found on COM14
上传项目出错

Try restarting your computer. Sometimes the COM port will get stuck in an unusable state and the restart will fix that.