Cancelling an insurance policy does not affect your credit score in any way.
So you can cancel an insurance policy at anytime as long as you're not behind in the insurance payments and it will be just fine and not harm your credit score.
Although if you do cancel your insurance policy and are behind in payments meaning you still owe the insurance company money for some months of insurance then that will be reported to the credit bureaus which will then lower your credit score.
However just cancelling your insurance policy will not affect your credit score.
Cancelling an insurance policy has no bearing on your credit score unless you still owe the insurance company money.