A verification code is sent to the email address you signed up with after your Prosper ID Protect subscription payment is processed.
Please check your spam folder to see whether 'firstname.lastname@example.org' appears on the list, if so mark it as not spam.
If you wish to use a different email address, it is possible to change it by tapping on the "Me" icon in the apps main dashboard and then by tapping on "Identity Protection". There you will be able to click on "Not Your Email?" to enter a new email address and resend the verification code. Please make sure that the email that appears there is indeed the correct one.