Any guidelines for debugging why the agent cannot assist my request?

I was trying to building some PoC application with a0, and for some reason, a0 agent keeps responses something like 'I'm sorry, but I cannot assist with that request.'. Is there some sort of safety guardline or restrictions? Or do you block some requests based on the content? (I think I did not write any aggressive stuffs, but the a0 keeps telling me that cannot help me)