You may be aware that in late December Congress passed a major tax reform bill. That has the IRS scrambling to get tax return forms ready for this tax filing season. They were waiting for the laws to pass.
Some forms are not finalized so you cannot file. The IRS has to finalize a number of forms and then approve the finalized forms in the TT software. Many state forms are not finalized either. No reason to be in a rush. The IRS will not be accepting returns until January 29 at the earliest, so filing early will not get you a faster refund. The earliest refunds will not be released until mid to late February. You just have to wait for the forms to be ready.