Ionic push notification device token missing in user android token value

I am trying to implement push notification service for my android app.
the user register in ionic push service but device token value not.

Please any one help me with this?

I have the same problem.

I have same problem.
I wonder if you solved it.

I checked here.
Many others have same issue.

Some people fixed, some people are not. The problem is that we do not know what condition makes it working.