Thanks a lot guys. I was about to respond to the logout/clear cash proposal above (which didn’t work) when @Chrisw response came in.
Made me test again with my user, well didn’t solve the issue either but apparently the dot changed colour from blue to red. We didn’t get the accept-notification request but had a closer look at the Mac settings and it turned out that it was set to off. Now we not only get the notification but also the number of messages waiting, cool! Case closed 
Thanks again to all involved.