An external shock without any IRF result

Stochastic simulations
1

Dear Professor Jpfeifer

I have set 7 external shocks for a DSGE model. Among them, there are six shocks’ IRF results are normal and reasonable. But the last one doesn’t have any result. And dynare told me that this shock didn’t correlate with all the variables.

May I ask how to solve this question?

Regards,
Modesty.

2

There is no general answer to this. Usually, you need to start from the smallest possible model to see where exactly the problem arises.