Several of the 2018 IRS tax forms are not available yet, therefore TurboTax is able to gather your information from your entry but cannot accept your return for filing to the IRS until all the forms required for your return are complete.
Below is a link of when federal individual tax forms are scheduled to be available and it states Form 5695 will not be available until 1/31/19. Therefore, your tax return cannot be filed until at least that date. (To find information for 5695, select TurboTax Online/Mobile option and then scroll down for Form 5695.)
https://ttlc.intuit.com/replies/3319876
