Self-employed health insurance deduction goes on Form 1040 Schedule 1 line 17 then to 1040 line 10, as long as the expense is not greater than your net self-employment income. If it does exceed your net self-employment income it gets split automatically. An amount equal to your net self-employment income goes on Form 1040 Schedule 1 line 17 and the remainder gets added in to medical expenses on Schedule A.
BUT do not enter any Health Care Marketplace insurance you bought. If you enter the 1095-A and select the "Self-employed and bought a Marketplace plan" box, it will automatically include those premiums in the SE Health Insurance section. So you shouldn't enter it again on schedule C.
Are you married? Be sure that Schedule C and the the insurance are entered under the same name.
