Sharepoint view won't export to excel, but items less than 5000.

I am creating a view that has 2 filters. The filters are on an indexed lookup column. If I create the view with one it works perfect and will export to excel. As soon as I add the second filter for a different value on the same lookup column it fails to export. The view displays items with no problem, but when I click export to excel I get the message "You do not have permission to view the entire list because it is larger than the list view threshold enforced by the administrator". I verified that the total items in the view is less than 500. Any ideas what I am doing wrong?