Application Menus with Pages Menus

[Adlago]

The menu may seem so:

[tenaki]

This doesn't work in the my set up

I have home page mysite.com

forums in mysite.com/forums

If I use  /calendar  for example it works on forums but get a 404 from the home page

So I guess I will have to use the full URLs eg mysite.com/forums/calendar etc etc