lab kickstart error (RH134)

On the first chapter of RH134 (Automating Installation with Kickstart):
When I run: "lab kickstart grade" to make sure all's ok to practice Installing a System Using kickstart....

I get this error:
Kickstart file available via HTTP...FAIL

the url entry in kickstart.cfg file points to http://classroom.example.com/content/rhel7.0/x86_64/dvd/

as instructed in step 2

thanks