What browser do you use? It sounds like he's using Chrome, for which the steps are:
Click on
View attachment 2622
Click Settings
Click Advanced at the bottom
Click Site Settings
Click Notifications
Under allow, there should be an entry under Allow for "
Featured Threads"
If there is more than one entry for Wondercafe2 under Allow, e.g. I also have one for "
Featured Threads", click the
View attachment 2622 to the right of it and choose Remove for the extra entries.
Firefox, IE, and Edge will have different, but similar, processes.