If you are having issues in Step 3 of the filling process and are trying to pay your TurboTax Fees with our refund transfer program, there's a known issue that it won't let you move forward if your “State refund doesn't cover TurboTax fees.” Even though, you might have enough on your Federal portion to cover it.
There's no date yet as to when this will be fixed.
However, if you would prefer to file now, you can do so by switching to pay your TurboTax fees with a credit card instead of using the pay with my refund.
See the link below for steps:
How do I remove Pay With My Refund fees in TurboTax Online and change my payment method?
If this is not your issue and you are having a different problem, please tell us what you are having when you try to sign/e-file.