Email return reason Daquan

Bounce Message: "invalid user", "user not found", "User unknown"
Cause of rejection: the recipient's user does not exist. the sender's email address cannot be found on the sending server because the email address in the sender's mailbox is incorrect.
Solution: we only need to confirm whether the address we entered is correct and try again.
Bounce Message: "quota", "hard limit", and "storage allocation"
Reason for rejection: the recipient's email address is full, and the email address we ship does not have enough space to receive. All emails will generate errors and be returned to your sending Address.
Solution: use other contact methods to let the recipient know that the mailbox is full, so that he can receive or delete some spam emails to free up space for receiving emails.
Bounce Message: "Not found", "host", "bad host domain"
Email return reason: the recipient's server name cannot be searched, mainly because the domain name or host address after @ is wrong when the email address is written.
Solution: Check the email address to see if any error is found.
Bounce Message: "exceeds", "Maximum Message Size", "data size"
Email return reason: the email sent is too large and the recipient's email server rejects the email. Currently, many email servers have to limit the size of the email to be sent. For details, visit the email website.
Solution: If you send a large number of emails, you can split the emails before sending them. For example, you can use oe to split the emails.
Bounce Message: "too success" and "less than 20"
Email return reason: there are too many users in the mail group. Some mail servers limit the number of users in the mail group. If this limit is exceeded, this error occurs.
Solution: we can control the number of users who send messages each time to about 20. If the number of users who send messages exceeds the limit, we can send the messages several more times.
Bounce Message: "connection timed out"
Bounce reason: the connection times out, mainly because of network problems during connection with the other server, leading to mail sending errors.
Solution: We can try sending the email several times. If it doesn't work, we can try again later.