Are you in the process of efiling and are referring to the 6-digit code emailed to you to verify your email address? And are you receiving a code in your email, but then it doesn't work?
If so, you have to leave the first screen open that asks for the code. You have to use a second window or a second browser tab to check your email to get the code, and then enter it in the screen you left open. If you close the first screen, the code will always be seen as invalid or expired. All modern browsers can open a second browser window or second tab.
Or if you have a smartphone, you can use your phone to check your email to get the code while leaving the TurboTax screen open on your computer.
Also see this :
FAQ: What if I'm having trouble with my filing verification code?
no matter what I do I still cannot receive the code. i have updated my browser and changed it as well. It's been two months and I still cannot receive the code.
READ the answer directly above your post.
If you still have an issue with the verification code after using the procedure in the FAQ, contact TurboTax support for assistance.
See this TurboTax support FAQ on how to contact Support - https://ttlc.intuit.com/questions/3401489