Error starting adb: Error starting application. Error: Activity not running, Intent could not be resolved

Question

Error starting adb: Error starting application. Error: Activity not running, Intent could not be resolved

Hi, I am trying to run "android yarn" in my reaction project. And I ran into the following error:

yarn android v0.27.5
$ react-native-scripts android
10:37:45 AM: Starting packager...
10:39:34 AM: Starting Android...
10:39:37 AM: Packager started!

To view your app with live reloading, point the Expo app to this QR code.
You'll find the QR scanner on the Projects tab of the app.

    <QR CODE>                                                  

Or enter this address in the Expo app search bar:

  exp://172.19.29.31:19000

Your phone will need to be on the same local network as this computer.
For links to install the Expo app, please visit https://expo.io.


    Logs from serving your app will appear here. Press Ctrl+C at any time to stop.

Error running adb: Error running app. Error: Activity not started, unable to resolve Intent { act=android.intent.action.VIEW dat=exp://172.19.29.31:19000 flg=0x10000000 }

(node:28009) UnhandledPromiseRejectionWarning: Unhandled promise rejection (rejection id: 1): TypeError: Cannot read property 'length' of null

I used the create-response-generator of a native application to configure my application, and here is my project structure:

<username>$ls
App.js          app.json        gen         package.json
App.test.js     assets          my-app-key.keystore stylesheet.js
README.md       components      node_modules        yarn.lock

I also tried to scan the qr code with my expo application to run my application on my phone, but it switches to 100% and then crashes from the application, or it gives a blue screen where the error is "Unclean" "Packager does not work in http :: 19003 "(even if the port I'm looking at is http: 19000).

"npm start", "a" android, : 11:40:20 AM: Android...

Error running adb: Error running app. Error: Activity not started, unable to resolve Intent { act=android.intent.action.VIEW dat=exp://172.19.29.31:19000 flg=0x10000000 }


 › Press a to open Android device or emulator, or i to open iOS emulator.
 › Press q to display QR code.
 › Press r to restart packager, or R to restart packager and clear cache.
 › Press d to toggle development mode. (current mode: development)

(node:31496) UnhandledPromiseRejectionWarning: Unhandled promise rejection (rejection id: 1): TypeError: Cannot read property 'length' of null
11:43:30 AM: Running app on SM-T560NU in development mode

11:44:01 AM: [sane] Warning: Lost connection to watchman, reconnecting..