It's saying my mortgage origination and acquisition dates are wrong, but I am typing what it says on my form. Any ideas?

The mortgage origination date (Box 3) on Form 1098 is the date on which the loan is funded, usually the date you closed on the property and signed the mortgage deed.  It's the date the mortgage originated with the original lender. 

The mortgage acquisition date (Box 11) is the date that the reporting lender acquired the mortgage. 

If the software is giving you an error, try to delete the form and begin again.

How do I view and delete forms in TurboTax Online?

• Open or continue your return in TurboTax.
• In the left menu, select Tax Tools and then Tools.
• In the pop-up window Tool Center, choose Delete a form.
• Select Delete next to the form/schedule/worksheet in the list and follow the instructions.

You have other dates wrong on the tax return that pertain to the property the mortgage is for. To help, I would need more details. What is this mortgage for? Initial purchase of a primary residence? 2nd home? Some kind of investment property? Raw land? Maybe it's a refi mortgage?

I had this same error and after spending 45 minutes fighting the program and another 15 looking for the number to call, the woman on support suggesting using a 4-digit year. It's been a long time since I've felt so foolish.