Typically this means that the message has been routed to your junk/spam. Please check these folders and your security settings to make sure the message is not being filtered out.
If you are using a work/professional email, it is likely that your company has specific email filtering that is blocking emails from our domain. If this is the case, you can check in with your IT team to have Respondent whitelisted on your email server.
If after the above steps you haven't received the email, reach out to firstname.lastname@example.org and we will investigate further.