Earlier this month, some Nexus users reported Google sync issues, including the Gmail app. Google then last week rolled out the v5.10 for its Gmail app with a fix for a sync issue involving Hotmail accounts. However, the company still seems to be working on another bug that restricts Nexus devices from getting notified about the incoming mails.
The Nexus users (including some Nexus 6P owners) experiencing the issue report that they are not receiving push notifications for Gmail until they open the app. The Gmail team has however addressed the issue on the Nexus forum. "The team has identified an issue which we believe is contributing to the syncing issue on Nexus devices. It is actively being worked on, and I'll continue to keep you all updated. In the meantime, please continue to post your experiences and/or if you have found any short-term workarounds," replied a Google employee. Some users also took the issue to Reddit.
Some users believe that the glitch could be stemming from the Doze feature. The headline feature which was introduced with Android 6.0 Marshmallow suspends certain tasks in the background in an attempt to save battery. Many users noted that disabling Gmail and some other Google apps and services from battery optimisation apparently fixes the issues.
"This is the answer that needs to be at the top. Gmail is getting dozed, causing sync to get disabled. Just remove it from battery optimisation and all issues should be resolved," a user wrote on Reddit. "Kind of sounds like the description for Doze's approach to battery life in general," another user chimed in.
Since there's no harm trying it, if you're facing a similar glitch on your device, you might also want to remove Gmail (and any other app impacted with the issue) as well as Google Play Services from Doze. To do this, open app drawer, go to Settings and select Battery. Click the three-dot button (context menu) and go to Battery optimisation. Click on Gmail and select Don't optimise option. Repeat the same with any other impacted app.