Push notifications seem to have stopped on Android app

Push notifications seem to have stopped on Android app

I'm not receiving notifications of new mail and I have to manually update the mail app to see new mail. This seems to have started today and is happening on both my Huawei phone and Samsung tablet. No changes on either since yesterday, signed out and signed in again, re-installed the app, checked the push settings and notification settings and all seems OK. New email appears in Outlook on my PC (IMAP).