Error 553: To send mail, first check your mail with a valid POP account
March 20th, 2009
Applies to:
NA
Description:
Occurs while sending a mail
Cause:
In order to prevent their use to send spam, some mail servers will require you to have a valid POP3 account and require you to login to that account before they’ll let you send mail through that mail server.
This is simple to handle in JavaMail. When you know that you’re dealing with such a mail server, make sure you connect to your POP3 Store on that mail server before sending mail.