Question

How do I fine out why my state return was rejected?

the email was accidently deleted

Upon logging in to your account, you can follow the instructions here:

Sign in to your TurboTax account and select Fix my return to see your reject code and explanation.
Follow any “fix it” instructions to update the info causing the reject.
Select File in the left-hand menu to refile your return, either e-file or file by mail.

Also, you can try searching your email trash account to retrieve the email.