Are you referring to the 6-digit verification code to verify when efiling? Are you receiving it by text or email?
If it's coming in email, then when you go to get the code, you must leave the first screen open that asks for the code. Use a different tab or different window to go to your email account to retrieve the code, then enter it in that first screen that you left open. If you close that first screen, the code will be seen as "invalid" or "expired." Another option is to leave the first screen open and to check your email account on your phone.
