Unless otherwise expressly provided, if a person, against whom an assessment has been made or a tax levied, claims that the assessment or tax or any part of the assessment or tax is invalid for any reason provided in subdivisions (1) to (6), inclusive, the assessment or tax may be abated, or the tax refunded if paid. The board of county commissioners may abate or refund, in whole or in part, the invalid assessment or tax in the following cases only:
(1) If an error has been made in any identifying entry or description of the real property, in entering the valuation of the real property or in the extension of the tax, to the injury of the complainant;
(2) If improvements on any real property were considered or included in the valuation of the real property, which did not exist on the real property at the time fixed by law for making the assessment;
(3) If the complainant or the property is exempt from the tax;
(4) If the complainant had no taxable interest in the property assessed against the complainant at the time fixed by law for making the assessments;
(5) If taxes have been erroneously paid or error made in noting payment or issuing receipt for the taxes paid;
(6) If the same property has been assessed against the complainant more than once in the same year, and the complainant produces satisfactory evidence that the tax for the year has been paid.
However, no tax may be abated on any real property which has been sold for taxes, while a tax certificate is outstanding.