A simple yet powerful feature that one might miss!
For this to work, you must install Synology's DS Finder on your mobile device (available for iOS and Android).
While you're on your LAN launch DS Finder on your mobile and let it find your DiskStation, login to it and turn on Push notification...
what desktop and mobile browser are you using?
For desktop I mainly use Firefox, but I'd like to replace it with Brave. Brave looks great, it's fast ... It's just not yet polished, still have some bugs, it's still not version 1.0.
On mobile I use Brave. Firefox is just not working for me...