This usually happens when something on the state tax return is not valid for e-filing.
Delete the state tax return and then go back to complete the state return.
See this TurboTax support FAQ for how to delete a state tax return when using the online editions - https://ttlc.intuit.com/turbotax-support/en-us/help-article/state-taxes/delete-state-return-turbotax-online/L8v9awRbh_US_en_US?uid=m005sold