I just had this same issue with two previous attempts at filing rejected within minutes with the third one pending. Certainly this is quite disconcerting, one observation that might be helpful to others. After I deleted form 8812 and recreated it I noticed differences between the earlier 8812 and later 8812. Specifically, old form 8812 box 4a, 4b, 4c and 6 listed number of dependents with a decimal point after the dependent number (1., 0., 1., and 0.) and after I deleted the form and created the new one dependent number boxes 4a, 4b, 4c and 6 now list dependent number as whole number without decimal point as 1, 0, 1 and 0) since my return is still pending rather than auto-rejected I can only guess that the addition of the decimal point in the number of dependents section was the reason for the rejection. Hopefully deleting the form and redoing it will solve this for others and I hope this will also work for me!
