Recently, a number of users have complained about issues when sending emails with their https://solveyourissue.com/smtp-verizon-email-settings/ email account due to AOL error message 475. For those with no ideaof the cause, this problem occurs when email servers spot suspicious activity on the account. This is why AOL prohibits accounts to send emails.

Simply put, if a the user experiences this issue, then the user will receive email but will not be able send emails via the AOL account.
https://solveyourissue.com/why-hotmail-not-sending-emails/