Phpmailer sends mails through SMTP. Some of the same sending contents succeed and some fail

-1001:SMTP Error: data not accepted.SMTP server error: DATA END command failed Detail: Requested action not taken: yA7MCgCnr+f1NbBiMH9EAQ--.5649S3, please try again SMTP code: 450 

Last , Find the mail server , The conclusion is ：

This email is because Fingerprint count The score is too high , It is even more than spam , Re delivery is required for judgment, so it is temporarily blocked . You need to adjust this threshold again

Some of the same content can be sent successfully, while others fail ： Some policy rules of intelligence are quite complex , For example, the same email will be integrated ip, Subject and sender or even sending time , Score the overall status of the day , When you send the first three emails of the same email, you may be able to pass , After the fourth message or after the transmission frequency rises , The score will rise sharply , First, put it into the user's dustbin , It may be normal to try again several times to abort the delivery , In the end, sending is forbidden directly .