there are two possibilities. what is the complete rejection message and code?
1) in your return you filled out a box that said you were covered by the Affordable Care ACT. it's in the medical expense section. you would need to delete both form 8962 and form 1095-A. the 1095-C is not the ACA and it is not entered in your return.
2) the IRS computers think you were covered. There are several possible reasons this could happen.
see https://www.healthcare.gov/taxes/
to see if there was coverage for you. if not then see 1)
if yes and you don't recognize it see how you can get a corrected 1095-A to be issued. this may require you to mail in your return.
