error in function call subsystem

Hi, I am new to using SimEvents blocks and triggered subsystems.

I have used function-call based trigger for a subsystem and sample time type as periodic. While I am executing the model I am getting an error

" The function-call initiator did not execute the function-call block on time step '0.0'."

How can the block be initiated at 0.0? Should I change any settings?

Thanking in advance