After the Beta update(78.0.276), notification does not shown at the windows action centre.

Hi RivMt, are you seeing any notifications from any websites in the Action Center?  Have you double checked that you are not in Focus Assist mode?  What is the version of Microsoft Windows that you are currently running?  Did you take and install an update recently?  The answers to these questions will help us understand what is going on.  Thanks - Elliot