Which state is it??? Here are a couple of possibilities for a state efile roadblock:
Did you already efile the Federal return first separately? If so, what is it's efile status? If efiled separately, you cannot efile the state return until the Federal return has been accepted.
Or perhaps one of your state forms is not yet available for efiling. Open your return interview and go through the REVIEW tab. Do you get any messages about why you can't efile it?
You can also check in this table to see if all your state forms are available:
State Forms Availability Table
https://ttlc.intuit.com/community/forms/help/state-forms-availability-table-for-turbotax-individual-...
