(1) No person shall act as an insurer and no insurer shall transact insurance in this state other than as authorized by a certificate of authority issued to it by the commissioner and then in force; except, as to such transactions as are expressly otherwise provided for in this code.

(2) Every certificate of authority shall specify the name of the insurer, the location of its principal office, the name and location of the principal office of its attorney-in-fact if a reciprocal insurer, and the kind or kinds of insurance it is authorized to transact in this state.

(3) The investigation and adjustment of any claim in this state arising under an insurance contract issued by an unauthorized insurer, shall not be deemed to constitute the transacting of insurance in this state.