IOS debugging error: Couldn't register com. xxxx with the bootstrap server

Today, I found that when I used the iPad for real machine debugging, the previous few times were okay, and then I was unable to run. The xcode output window displays the following information:

Couldn't register com. autodesk. Material-Demo with the bootstrap server. Error: unknown error code.

This generally means that another instance of this process was already running or is hung in the debugger.

This indicates that a process is running in the debugger.I tried to delete the app on the iPad, but it didn't work.

Search online: follow these steps:

Disconnect the data cable and restart the iPad.

In Xcode, clear the project, product --> Clean:

Reconnect data cable

Restart debugging on the iPad.

Successful!