Hard to know .... you shouldn't be attempting to amend right now.
The proper final Federal 1040X forms are not expected to be software ready until 18 Feb....but the way things are going..it could be March. SO the proper links to the various lines on the forms may not be in there yet.
Once the 1040X forms are finalized, you should be able to review what the problem is in "Forms Mode" using the Desktop software (not sure what you could do to check the various lines with the Online software).
____________*Answers are correct to the best of my knowledge when posted, but should not be considered to be legal or official tax advice.*
