Facebook notifications disappeared in Mojave

Hi,

I've recently moved from win to mac, and one of the little things i liked about the new system was, when I recieved a message or notification on Facebook, no matter what I was doing (pages, mail, movie, etc.), I would recieve a small notification in upper right corner. Ever since I updated from High Sierra to Mojave, this feature disappeared completely. Is there any way how to turn it back on? I quite miss it.

Thanks in advance