Not reading the google play Policy
Begin first to read the policy to be sure that your app is compliant with the google privacy policy.
Publishing Directly in Production Canal
Not having a Privacy Policy Website
It’s very important when you publish your app, to have a privacy policy website that describe correctly what your app stand for.
This is the way you communicate with google team and also with your users.
Forgetting versioning
Versioning is the way that every programmer identify their code and when you publish an app on play store, you have to upgrade the version of your code to help google to know that it’s a new version.
You can know more about that here : https://developer.android.com/studio/publish/versioning
Use different hash key
The hash key is the signature of an app and in when you build your app for production, in React Native, Flutter or android, the program will generate a key for your app and this key will be unique for your app.
In case you publish other version of your app, but with a different key hash, this will not be published by google for security reason.