I've finally got around to installing and using Whatsapp but I'm having an issue with notifications. If the phone (Samsung XCover 4 on Nougat) screen is on and unlocked then I get notifications. If the phone is (not always but mostly locked) with the screen off I get nothing until I unlock it. I've tried everything I can think of and everything I can find on Google. Does anyone have any clever ideas? I've turned off the battery saving, turned on sync, allowed notifications whenever it wants and still nothing.