To gain access to Gmail without requiring a verification code, you may be forced to utilize recovery options such as backup codes, recovery emails, or phone numbers you have established for the account. If you lack access to those, you can try account recovery by answering questions to verify your identity. Here is a more detailed account: Backup Codes If you've got 2-Step Verification turned on, you can create backup codes to use instead of verification codes in case you're unable to get to your phone or other methods of verification.
