hangouts not syncing from PC to Nexus 6 I have the hangouts extension installed in chrome on windows 7 and windows 8 PCs and a stock Nexus 6 which has hangouts installed as a system app. When I send and receive messages on my PCs my phone doesn't update with those messages sent on the PC. I also have a Nexus 7 on lollipop and it syncs messages just fine. My LG G3 also syncs messages. I have tried wiping cache/data in the app, signing in and out of chrome and the google account on my phone, factory resetting the phone, etc. 

Anyone have any ideas? I tend to switch between my phone and PC all the time and would live to be able to have synced conversations.
It looks like GCM Push Notifications don't work with IPv6. I disabled IPv6 entirely in my router and now everything is fine. Though IPv6 was enabled for the past two years and I didn't have any kind of issue. Let's hope a Play Services update fixes it. 

Here is where I got the answer. On rooted devices, you can install [ROOT] Disable IPv6 to fix the problem.