Google is aware of this problem, and a number of Googlers have already acknowledged and replied to the Issue Tracker thread, so we know the company is looking into it.
Contrarily, my Nexus 9 and old One Plus One sync notify me just fine.” “I also am not receiving gmail notifications after the phone has been sitting idle for a while,” writes another.
“For example, if I leave my Nexus 6 with Android 6 (with November 1 update) idle for 30 minutes, then send a test email to my gmail email, I won’t receive a notification.” Another thread on the Android Issue Tracker forum has been starred by more than 500 people as I write this post, suggesting the issue is rather widespread among Nexus users.
Unfortunately, it’s still not clear what is causing this problem at this point.
A number of workarounds that could fix the issue for some users include wiping the cache, resetting your Google account, and even flashing back to earlier builds of Marshmallow.
( Some Android users have been encountering issues with Gmail syncing for a good while now, but Google is finally getting ready to roll out a fix next week.
The Gmail sync issues seem to be quite widespread, with numerous users reporting that they received notifications late (or not at all).
The sync issues reportedly affect both Gmail and Inbox by Gmail.
Nexus smartphone owners are reporting a mysterious sync issue with a number of popular Google apps, including Gmail, Inbox, and Google Now.
The issue appears to be affecting those who are running the latest Android 6.0 Marshmallow software.