It is no longer possible to resubmit a rejected 2018 personal tax return, as e-filing has shut down for tax year 2018. You would need to start fresh using the TurboTax CD/Download version and then printing and mailing in your tax return.
Refer to the TurboTax FAQ's below for instructions:
Use this link, to help find the rejection code, so it can be corrected on your new filing:
How do I fix a rejected return?