I had an issue in my React-Native project which was working fine earlier but suddenly it stopped working. Whenever I used the command:
react-native run-andro
If you have created your project with the expo command, like expo init projectname, then afterwards you have to eject your project:
expo
expo init projectname
expo eject
If you have created you project by react-native init projectName then you have to use
react-native init projectName
react-native eject