Top 10 causes that you emails are not delivered?

Top 10 causes that you emails are not delivered?

If you are a MIS of a company, what do you think occupy most of your time throughout the day? Perhaps, it is when you need to explain to users why they are unable to send email messages, right? Seemingly, error messages in Outlook appear to be grammatically simple, but why is it hard to pop up with solid answers?

It is understandable that our colleagues don’t understand after staring at error messages for 10 minutes because they are not good at it. The worst part is some of them freak out and refuse to listen to you.

For your information, I list 10 most common error messages bouncing back from a paid or free mail server and their causes so you have something to stuff their ears or pint them out and give everyone a copy:

1. Recipient’s mailbox is over its quota - When this happens, you really cannot do anything about it.
   Error message:EX. 1 - 452 Message for **** would exceed mailbox quotaEX. 2 - 450 **** : out of quota
2. Recipient’s mailbox does not exist -Most commonly mistakes committed by senders and they usually deny it.Error message:EX. 1 - 451 Requested mail action not taken: mailbox unavailable
3. Email message size is over recipient’s incoming mail size limit -Sender put an oversized attachment in the outgoing mail and recipient mail server rejects it
   
   Error message:
   EX. 1 - 421 The Size of the Message Exceeds the Recipient's Size LimitsFor Incoming EmailsEX. 2- 450 5.2.3 Msg Size Greater Than Allowed By Remote Host
4. Recipient’s mail server has a graylisting policy against incoming mails - Mails will not be delivered in real-time until a second attempt. Recipient’s mail server takes the blame.
   
   Error message:EX. 1 - 451 4.7.1 Temporarily rejected. Try again later.EX. 2 - 451 Resources temporarily unavailable. Please try again later.EX. 3 - 450 4.7.1 **** : Recipient address rejected: Policy Rejection-Please try later.EX. 4 - 450 4.7.1 **** : Recipient address rejected: Try again, see ****EX. 5 - 451 DT:SPM ****, ****, please try againEX. 6 - 421 ****, SMTP service not ready
5. Your mail server has been sending out too many spam mails -It is a bit shameful to tell the truth but your mail server sends out too many spam mails and recipient’s mail server has temporarily or permanently deny any mail from your server.
   
   Error message:EX. 1 - 421 4.7.0 [GL01] Message from (*.*.*.*) temporarily deferredEX. 2 - 452 Too many recipients received this hourEX. 3 - 421 #4.4.5 Too many connections to this host.EX. 4 - 550 5.7.1 Our System Has Detected an Unusual Rate of UnsolicitedMail Originating From Your Ip Address. To Protect Our Users From Spam, MailSent From Your Ip Address Has Been Blocked. Please Visit Http://www.google.com/mail/help/bulk_mail.htmlTo Review Our Bulk Email Senders Guidelines
6. Your mail server’s PTR (reverse IP resolution) cannot be resolved by recipient’s mail server -Technically, this is a DNS issue that commonly happens in IDC or educational institutes where your IP fail to be reversely resolved into your mail server’s hostname. However, most ISP does provide a default value for the reverse IP resolution. Make sure your mail server have one.
   
   Error message:EX. 1 - 421 Refused. You have no reverse DNS entry.
7. Sender from your end typed recipient’s email address wrong -Com’on! Please gently acknowledge users that they key their own email address wrong. Please advise them to correct it within their email software.
   
   Error message:EX. 1 - 451 Domain of Sender Address Does Not Resolve
8. Physical storage dedicated for incoming mails on recipient’s mail server is full -Apparently, this is no one’s fault. Please advise your users to inform their recipients by other means such as phone call, text message or social network software.
   
   Error message:EX. 1 - 452 Requested Action Not Taken: Insufficient System StorageEX. 2 - 431 The Recipient's Mail Server Is Experiencing a Disk FullCondition
9. Recipient’s mail server put your mail server on their black list and refuse for no reason - This situation is often caused by your mail server’s IP, your mail server’s reverse IP resolution value or geological location to which recipient’s mail server just denies it for no reason. Another occasion is that your default mail server's reverse IP resolution provided by your ISP is not acceptable by recipient's mail server.
   
   Error message:EX. 1 - 552 Sorry, We Don't Allow Mail From Your HosEX. 2 - 554 Your Ip (*.*.*.*) Is Dynamic Ip Address, Use Your Isp SmtpServer Instead
   
   Error message EX. 2 - 554-kundenserver.de (mxeue004) Nemesis ESMTP Service not available  554-No SMTP service  554-Bad DNS PTR resource record.  554 For explanation visit http://postmaster.1and1.com/en/error-messages?ip=*.*.*.* c=rdns. You can contact support e-mail of hosting@1and1.com and explain your situation.
10. Recipient’s mail server has detected unacceptable content within mails from the sender from your endSome recipient mail servers just refuse to accept emails containing files with certain extensions such as .EXE or .ZIP.
    
    Error message:EX. 1 - 554 5.7.1 The File Xxx Has Been Blocked. File QuarantinedAs:b100493a.xxx