Usually Parse notifications are received and it works well on my test android app.
when i added Onesignal to my project, Parse notification are not received anymore ?
What can be a possible conflict ?
By default Parse uses it own "Google Project number" (Sender ID). For OneSignal you setup your own however if you have 2 different project numbers in your app the previously registered one will become unsubscribed.
If you're migrating over to OneSignal from Parse you should follow the blog post below to keep your channels. https://onesignal.com/blog/important-note-for-android-parse-push-users/