Alabama State Tax Schedule D Negative Amount Not Eligible for e-file

I filed my son's Federal and Alabama state taxes and both of us had negative amounts received on Schedule D.  When I filed his return, it appears to have filed with no issues.  When I'm in final review for my taxes, I get ineligible for e-filing with a reason stating "Returns with a negative amount received on Schedule D are not eligible for electronic filing."  I do not remember seeing this message when doing my son's taxes and I've looked at the Alabama Form 40 and Schedule D instruction booklet and have not yet found a rule like this.  Might someone be able to point me to where this rule is stated for Alabama and second, what action should I take on my son's taxes that are already submitted via e-file?