Return Letter

Keywords or Return Letter Content Causes and Solution
Return letter:User user@dd.net.cn is not found in Server. It is possible that return letters are generated because you fill Chinese characters or other unsupported characters in address field.Generally,when there are Chinese characters in recipient's address,we give message "You have used incorrect format of address,and the system has correct it automatically.Please confirm the operations of system is correct,enter "Cancel and change by yourself" if not.
Keyword: Quota 、 exceed 、 hard limit 、 exceeding 、 storage allocation
Return letter content:
1 ） <user@163.net> : Quota exceed the hard limit for user user01@163.net
2 ） <user@themail.com> : host …… said: 552 This person's account is exceeding their quota.
3 ） <user@hotmail.com> : exceeded storage allocation
4 ） <user@dgpage.com> : 552 Channel Size Limit exceeded
There are not enough space in recipient's mailbox to receive your email.Fail to receive and return to your email address,please contact the receiver in other ways or inform the receiver of deleting useless emails to free some space.

Keyword: not welcome 、 content rejected 、 Message blocked 、 Recipient reject

Return letter information examples:
1) <user@163.net> : This Message is not welcome
2) <user@163.com> : Error: content rejected <user@163.net> :
3) Message content rejected <user@21cn.com> : Message blocked.
4) <user@sohu.com> : host ……said: 550 Recipient reject
5) <user@126.com> ： 550 CoremailSys:Your message was blocked by NetEase AntiSpam+

It is possible that the receiving users set some rule(for example:keywords filter,users filter,email size filter,etc),please inform them check the settings.

Keywords: banned 、 isn‘t in my list of allowed rcpthosts 、 domain is not welcome 、 Connection refused 、 Relaying denied 、 message blocked
Return letter examples:
1) <user01@weefth.com> : 571 user02@163.net... from mail01j.rapidsite.net You are banned, contact yourlocal admin.
2) <user@foodomain.com> : 553 sorry, that domain isn't in my list of allowed rcpt hosts
3) <user01@cbnweb.com> : 550<user02@cbnweb.com>... Relaying denied
4) <user01@home.com> : 550 5.0.0 > <user02@163.net> : Mail originating from that domain is not welcome here
5) <user@foodomain.com> : connect to mf2.cbnweb.com: Connection refused
6) <user@public.guangzhou.gd.cn>: host…… said: 553 From <user@163.net>, message blocked. 		The causes are that you are likely to be listed in blacklist or not in list the receiver's system allow,please contact them to open whitelist for you or let system administrator to check log to make the process of sending clear.
Keywords: Host not found 、 bad host 、 domain unreachable 、 Connection refused
Returning letter example:
1) <user@sian.com> : Name service error for domain sian.com: Host not found : Name service error for 2 、
2) <user@zdl.net>:domain zdl.net: Host not found, try again
3) <user@hot.163.net> : Name service error for domain hot.163.net: Host not found
4) <user@.powerise.com.cn> : bad host/domain syntax: ".powerise.com.cn"
5) <user@shou.com> : connect to shou.com: Connection refused
6) <user@aadf.com> : domain unreachable (Domain does not exist.)
The host or the recevier's domain is incorrect or the domains cannot be resoluted correctly by system.And it fail to deliver because of incorrect domain behind @ to a larger extent.
Keywords: error in command 、 syntax error
Return letter examples:
1 ） <user@ap.dragoco.com>: host ……said: 500 error in command
2 ） <"" m83832000@yahoo.com.cn user""@sina.com>: host ……said: 555 - syntax error (# 5.5.4 )

The major causes are the receiver system cannot recognize software or instruction system of sender when delivering to connect to receiver's system.Please use common software(for example Outlook Express or Foxmail) to compose email,or in the way of Web to send emails to reduce to chance to fail.

If it cannot be solved,please send again later.And the other kind of causes is the sender enter invalid characters(for example,“””“/”“”“^”) in recipient address field and these characters lead to sending failure.
Keywords: 550 CoremailSys:System is busy.
Return letter content:
1) The message to sales@flo.com.au is bounced because :
550 CoremailSys:System is busy.
2)You send to sales@flo.com.au Emails are returned because:
550 CoremailSys:System is busy. 		Return letter cause:because some keywords in your email subjuct or content triggered filter rules of system and your email are returned.
Solution:You can change the subject of email or let anti-spam system administrator to check rules according to return letter.
Keywords: exceeds 、 maximum message size 、 Data size
Return letter information examples:
1) <user@brilliantprint.com.hk> : 552 Message size exceeds fixed maximum message size: 7372800 bytes
2) <user@brilliantprint.com.hk> : 552 5.2.3 Message size exceeds fixed maximum message size (7200000)
3) <user@pub.xaonline.com> : host smtp.xaonline.com[61.134.1.143] said: 552 Data size must not exceed 4096K bytes.
Return letter causes: Because of the oversize of email from sender,the system of receiver reject this email.
Solution: This kind of failure caused by the receiver's system protection mechanism:rejecting oversized email from sender.You can use Division feature of Outlook express to divide an email to several parts to send.
Reture letter example:
1) The message to julia.dlc@aircity.com.cn is bounced because : SMTP error, MAIL FROM: 553 sorry, your mailserver is listed in bl.spamcop.net(Please see: Blocked ? Seehttp://www.spamcop.net/bl.shtml?61.135.129.15.bl.spamcop.net), mail from is not accepted here 		Return letter causes: http://www.spamcop.net 61.135.129.15 was listed in blacklist.
Solution:You can request mail system administrator to contact the person who in charge of blacklist to remove.
Keywords:Operation to emails in the queue timed out, Rcpt queued timeout, Connection timed out
Reture letter example:
1)You send to sky_lee555@sina.com are return because :Operation to emails in the queue timed out.
2) The message to betty.yu@cn.flashelec.com is bounced because : Rcpt queued timeout
3) <user@iris.sipp.ac.cn> : connect to iris.sipp.ac.cn: Connection timed out <user@126.COM> : no found target server 		This kind of return letters have two causes:
1) Connection to server timed out.(Mail system does exist in this domain,but it cannot be connected due to network problem,especially between countrys or the north and south.)
2) It is possible that receiver domain does not exist at all.And it cannot be connected.
Solution:
1) Because of onnection to server timed out due to network problem,email delivery fails.Please try to deliver this email wait a minute or exchange to telcom system if user frequently use in south.
2) Please check whether the receiver address exists and is correct.You also find domain MX records through NSLOOKUP.If you find out MX record,you can Telnet this IP port 25 and check wheter it is connected.

1) Return information about rejecting IP connection:
Return letter keywords: 520 This IP has too many concurrents, please try again later

2) Return information about rejecting user connection:
Return letter keywords: 521 This User has too many concurrents, please try again later

3) Return information about rejecting email content:
Return letter keywords: 550 System is busy.

4) Return information about rejecting Helo query failed email:
Return letter keywords: 450 Query HELO/EHLO Host Domain fail

5) Return information about rejecting Helo information failed email:
Return letter keywords: 550 Reject HELO/EHLO Host Domain

1) Return information about rejecting IP connection:
The causes and solutions:When you forward emails or auto reply by virus computer,the system limits the number of forwarding emails and IP connection to servers.If you exceed the limit,return letter is generated.

2) Return information about rejecting user connection:
The causes and solutions:The system limits the number of connections to server per minute and per user.If you exceed the limit,return letter is generated.Please contact system administators.

3) Return information about rejecting email content:
The causes and solutions:If email subject or content trigger system rules,please change your subject or content of email or contact system administators.

4) Return information about rejecting Helo query failed email:
The causes and solutions:It is return letter user test through commands.

5) Return information about rejecting Helo information failed email:
The causes and solutions:It is return letter user test through commands.
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