Why is no smoke coming out of my disposable pen?

Could you please explain why there's no smoke emanating from my disposable pen? Is it a sign of malfunction or a result of user error? Could the lack of smoke be attributed to insufficient battery power, a clogged airway, or a depleted liquid supply? Additionally, are there any safety concerns I should be aware of if I continue to use the pen without smoke? Finally, what steps can I take to resolve the issue and ensure proper functioning?