Push notifications does not work on Android client

I tried to configure the android client with Nextcloud 20.0.2.
Everything works well but the notifications don’t work and I have an error “the push notifications are not available at this moment”.
I found old posts here with similar issues but without a solution.
The battery settings are correct and until now the push notifications worked well.
I needed to reconfigure the client and stoped to work

What can I do to solve this issue?

Solved with the last Android update