N.D. Cent. Code § 26.1-12-19
If the premium on a policy issued by a mutual insurance company is not paid in cash or in an unconditional note within sixty days after the date of issue of the policy, the policy becomes void and remains void during the period of nonpayment of premium. Upon the payment of the premium, the policy reattaches if no loss has occurred thereunder while the policy was void. If, however, the company has issued a policy with a mortgage clause making loss, if any, payable to the mortgagee to the extent of the mortgagee's interest and not exceeding the amount of the policy, the company, notwithstanding the nonpayment of premium or contingent mutual liability, is liable on the policy to the mortgagee until the secretary of the company has notified the mortgagee in writing that the premium or contingent mutual liability has not been paid and the mortgagee has twenty days from the date of the notice in which to pay the same, and in default of the payment, the liability of the company to the mortgagee ceases.
N.D.C.C. § 26.1-12-19