Mali Graphic Debugger can not work on Android 8.0

PC : 

Mali Graphics Debugger from Arm Ltd.

Version: 5.1.0.8a0102de

i follow the step of documents about using mgd on unroot-devices 

my phone is huawei P20  Mate 20 V10  and Oppo r15 , they are all android8.0+ 

when i startup the my app(with System.load libmgd.so )，MGD on PC do not trace anything 

I check the log on phone , they show:

···

E/mgd_interceptor: (8352): SocketMessagePort: Unable to connect socket: Unable to connect socket: errno = 13
W/mgd_interceptor: (8352): GatorConnection: Not connected to gatord, the application will run normally but Streamline will not collect annotations. To collect annotations, please verify you are running gatord 5.22 or later and that SELinux is disabled.
E/mgd_interceptor: (8352): Interceptor: MGD failed to read the process whitelist file: No reason provided. (Does the file exist & have correct permissions?)
W/mgd_interceptor: (8352): Interceptor: MGD_HEADLESS_CONFIG_FILE not specified, falling back to '/sdcard/mgd-headless.conf'
E/mgd_interceptor: (8352): Interceptor: Headless config file specified was not found
E/mgd_interceptor: (8352): Interceptor: Unable to create message port - using null

···

anyone has idea to fix the socket permission error ?