Hi,
The personal tax account and check my state pension calculators have been set up to show shortfalls at Class 3 rate. They will not be able to establish that your husband may be eligible to pay shortfall years at Class 2.
If you wish to confirm what shortfalls you and, or, your husband may have and whether these may be payable at the Class 2 rate, and are not within 6 months of UK state pension age, you can contact our National Insurance team for international customers:
National Insurance: non-UK residents
You can also complete the CF83 again and note that its just for shortfall advice, as these forms are set up with paying future voluntary National Insurance contributions in mind.
Thank you.