·501 This server will not accept forged credentials[2016-5-9]
·550 Sender frequency limited[2016-5-9]
·553 can't verify FROM domain in DNS;domain does not exist[2016-5-9]
·450 Client host rejected: cannot find your hostname[2016-5-9]
·552-5.2.3 Your message exceeded Google's message size limits[2016-5-8]
·550 5.7.606 Access denied, banned sending IP[2016-5-8]
·451 Temporary internal failure, please contact your email administrator[2016-5-8]
·501 Bad address syntax[2016-5-8]
·550 Ip frequency limited[2016-5-8]
·网易邮箱常见退信说明[2016-5-8]
·No mail servers appear to exists for the recipient's address[2016-5-8]
·553 Blocked Using Spam Pattern, Your Message May Contain The Spam Contents[2016-5-7]
·553 you don't authenticate or the domain is not allowed relay[2016-5-7]
·Recipient address rejected: Access denied[2016-5-7]
·421 4.3.2 Service not available[2016-5-7]
·554 Sorry, message looks like SPAM to me[2016-5-7]
·The DNS query has failed,MX/IP resolved failed[2016-5-7]
·Remote server closed connection的原因分析[2016-5-7]
·552 Requested mail action aborted: exceeded storage allocation[2016-5-7]
·554 5.7.1 Recipient address rejected: receiving function of recipient is limited[2016-5-7]
·550 Local user only or Authentication mechanism[2016-5-7]
·501 Connecting IP must have valid PTR,554 invalid DNS PTR resource record[2016-5-7]
·451 Service unavailable[2016-5-7]
·550 #5.1.0 Address rejected.[2016-5-7]
·453 Mail queue error[2016-5-7]
·550 5.7.1 Relay access denied[2016-5-7]
·554 5.7.1 You are not allowed to connect[2016-5-7]
·550 mailbox rejected[2016-5-7]
·554 Zodiac RBL hit, please contact...[2016-5-7]
·反垃圾邮件技术---邮件头过滤[2016-5-7]