The program works so you have done something wrong by accident. You may have not correctly indicated you had eligible coverage all year. I can only suggest deleting your W-2 and entering it again, keep clicking next to go through all the steps, don't jump around. There should be a question about your coverage. Also, run the HSA interview on the deductions and credits page again carefully.
If you are filing as single or married filing separately, are you by chance using an account that was used in the past to file a joint return? That could be the problem, there are hidden program worksheets that make it almost impossible to remove every trace of a spouse, there may be something hidden that is affecting your eligibility.