Blueprint + Cascade Fireworks system for my peeps!

I want to trigger the fireworks by stepping into a trigger volume. I added this to the BP_Fireworks_launcher:

But it doesnt work, error message is " Infinite loop detected in Bp_Fireworks_Shell, asserted during set timer by function name with the following call stack"

I know it should be simple to do it, but i am a beginner in blueprints, how someone can point me the right way.