The IRS hasn't finalized one or more of your forms.

[PatriciaR]

Some IRS forms are not yet available/finalized. Please see the TurboTax FAQ link below for IRS forms availability and the dates they will be available. 

 While in your TurboTax return, click the Review tab at the top of the screen to view the forms and schedules that have not been finalized in your tax return.  Once the forms are available, you will be able to complete your return.

 https://ttlc.intuit.com/replies/3319876