@Edna try this
While viewing the forum site, you can change the notifications permission using the Permissions panel of the Page Info dialog. To call that up, either:
right-click a blank area of the page and choose View Page Info > Permissions
(menu bar) Tools menu > Page Info > Permissions
click the padlock or "i" icon to the left of the site address, then the ">" icon, then More Information > Permissions
Scroll down to "Receive Notifications" and you can check the "Use default" box (so you are prompted in the future) or uncheck that box and select the permission you prefer (for example, Block).
There's no save button for this panel, changes are saved as you go.