Google Hangouts - No Notifications

[AC Question]

Started happening yesterday, I've noticed that I'm not receiving my messages on my Samsung S7 through Google Hangouts until I manually open the app on my phone. I can have my Laptop with gmail, and/or my Apple tablet with Google Hangouts, and those devices will receive a notification of a new message even when locked or in screensaver. Samsung S7 will be open and right next to it, no notification. Once I open the Samsung S7's Google Hangout app, message is then received.
I've restarted
Any thoughts?