New User Not Able to Receive Emails for Confirmation or Password Reset

One of our users, <personal information- redacted>, has an active account but has been unable to use this account as the user never received the confirmation email and cannot reset the password. Last time we had a similar problem, one of our users was placed on a block list because initially their first few emails had bounced. Could you please see if this user is on that list and remove them if so?