I'm new to mapmaking and am trying to get my zombies to spawn for the first time

I've been following a YouTube tutorial

Zombies are not spawning here's what I've done

*set spawners
*set volume
*set kpv's

I am getting the yellow link from the spawners to the volume

When I start up my map this is the error I get

https://imgur.com/a/Ul1xy

I could probably upload my map files if you would like

Any help would be appreciated

Have you correctly set up your zones in mapname.gsc?
Have you double-checked your spawner kvps?

Please upload a screenshot of your kvps.

Zone setup in mapname.gsc should look similar to this:

	add_adjacent_zone( "start_zone", "zone01", "enter_zone01" );
	add_adjacent_zone( "zone01", "zone02", "enter_zone02" );
	add_adjacent_zone( "zone01", "zone03", "enter_zone03" );
	add_adjacent_zone( "zone02", "zone04", "enter_zone04" );
	add_adjacent_zone( "zone04", "zone05", "enter_zone05" );

Spawner kvps should look like this: