If you are not receiving the security code associated with your Blockstream Green wallet, it may be helpful to confirm the email address or phone number that is being used for two-factor authentication.
Open Blockstream Green and login to your wallet.
Click the cog icon to go to the settings page.
Navigate to the Security tab in the settings sidebar.
Scroll down until you see TWO-FACTOR AUTHENTICATION. You will now be able to see the email address or phone number associated with your wallet.
Note: For security purposes, your email address and phone number will be partially masked. However, there should still be enough information for you to identify the details of your activated 2FA method.