I want to display the username in the profile page

[Kumaravel786]

I only want to display the username in the profile page i had done what you did but i am getting this error.
ERROR FirebaseError: Missing or insufficient permissions.
at new FirestoreError (http://localhost:8101/vendor.js:100558:28)
at JsonProtoSerializer.push../node_modules/@firebase/firestore/dist/index.cjs.js.JsonProtoSerializer.fromRpcStatus (http://localhost:8101/vendor.js:115223:16)
at JsonProtoSerializer.push../node_modules/@firebase/firestore/dist/index.cjs.js.JsonProtoSerializer.fromWatchChange (http://localhost:8101/vendor.js:115720:44)
at PersistentListenStream.push../node_modules/@firebase/firestore/dist/index.cjs.js.PersistentListenStream.onMessage (http://localhost:8101/vendor.js:111675:43)
at http://localhost:8101/vendor.js:111604:30
at http://localhost:8101/vendor.js:111644:28
at http://localhost:8101/vendor.js:101896:20
at ZoneDelegate.invoke (http://localhost:8101/polyfills.js:3365:26)
at Zone.run (http://localhost:8101/polyfills.js:3130:43)
at http://localhost:8101/polyfills.js:3861:36