we don't know how your capital loss arose, but IRC section 469 contains the rules for passive activities
.(1)Certain income not treated as income from passive activity
In determining the income or loss from any activity—
(A)In general
There shall not be taken into account—
(i)any—
(I)gross income from interest, dividends, annuities, or royalties not derived in the ordinary course of a trade or business,
(II)expenses (other than interest) which are clearly and directly allocable to such gross income, and
(III)interest expense properly allocable to such gross income, and
(ii)gain or loss not derived in the ordinary course of a trade or business which is attributable to the disposition of property—
(I)producing income of a type described in clause (i), or
(II)held for investment.
so perhaps you need to go back to the return preparer and inquire why the loss is passive
