Entering HSA Contribution Says I Overcontributed

Did you answer the HDHP questions? Not only must a HSA contribution be below a certain amount but you also must be covered by a high-deductible plan for the right amount of time in the year.

Here is the first such interview question.

Since you are using windows desktop software, you can check out the worksheet/forms directly. That is often very helpful and the reason why many of use prefer the desktop versions.  See below and check over the detailed login on the Form 8889 include the smart worksheets to see where TT has decided you over contributed. Then you can correct your data entry if you missed something (like saying you were covered by a HDHP.)