phpmailer - The following SMTP Error: Data not accepted

The "SMTP Error: Data not accepted" is a common error message that can occur when using the PHPMailer library to send email messages. This error typically occurs when the SMTP server you are using to send the email message is unable to accept the data you are sending. This can be caused by a number of different issues, such as incorrect SMTP login credentials, a failure to connect to the SMTP server, or an issue with the email message itself. To resolve this error, you will need to troubleshoot the specific cause of the issue and make the necessary adjustments to your code or configuration.