--- title: "Find email delivery failures in Exim" description: "In this article we are going to go over how to quickly review the entire mail log for your VPS or dedicated server in order to find delivery failures that are occurring. Email delivery failures can..." url: https://www.inmotionhosting.com/support/email/find-email-delivery-failures-in-exim/ date: 2013-01-16 modified: 2021-08-16 author: "InMotion Hosting Contributor" categories: ["Email"] type: post lang: en --- # Find email delivery failures in Exim In this article we are going to go over how to quickly review the entire mail log for your VPS or dedicated server in order to find delivery failures that are occurring. Email delivery failures can happen for a large number of reasons, for a more in-depth explanation on these types of issues you can check out my article on [why does email bounce](/support/email/email-bounce-bounceback-error/)? In order to follow the steps below you’ll need [root access](/support/server/ssh/root-access-faq/) to your server. ## Locating email delivery failed messages 1. [Login to your server via SSH](/support/server/ssh/how-to-login-ssh/) as the root user. 2. Run the following command to get a sorted report of the users with the highest amounts of delivery failures: `grep "for .*@.*" /var/log/exim_mainlog | grep "<= <>" | awk -F"T=" '{print $2}' | awk '{print $NF,$0}' | awk -F" for" '{print $1}' | sort | uniq -c | sort -n` **Code breakdown:** grep “for .*@.*” /var/log/exim_mainlog Locate lines in the Exim mail log that include any variation of “for user@domain.com” grep “<= <>” Locate lines that are being sent from a null sender, which indicates a bounce back awk -F”T=” ‘{print $2}’ Use the **awk** command with the **F**ield seperator set to **T=** which is the subject line in the mail log, then only print the **$2**nd column of data. awk ‘{print $NF,$0}’ | awk -F” for” ‘{print $1}’ Use **awk** to print **$NF** which is the very last column, which is the email address. Then run **awk** again with the **F**ield seperator set to ** for** and then print out only the **$1**st colum of data (this strips the email user off of the end of the line). sort | uniq -c | sort -n Sort all of the data by the email users, then uniquely count them, and finally sort those counts by lowest to highest. This will give you back data looking like this: `573 support@example.com "[Mail delivery failed: returning message to sender](/support/email/mail-delivery-failed-returning-message-to-sender/) 663 user@example.com "Mail delivery failed: returning message to sender 871 test@example.com "Mail delivery failed: returning message to sender 1282 help@example.com "Mail delivery failed: returning message to sender` ## Investigate cause of delivery failures Now that you know one user in particular **help@example.com** had the most delivery errors, you can use the steps below to investigate the cause of these problems. 1. Run the following command to find the latest delivery failure:`grep "Mail delivery failed:" /var/log/exim_mainlog | grep help@example.com | tail -1` This should give you back the full line from the Exim mail log that contains that error: `2013-01-16 14:45:34 1TvYvW-0006AC-ER <= <> R=1TvYvW-00069r-Au U=mailnull P=local S=2012 T="Mail delivery failed: returning message to sender" for help@example.com` Copy the messaged ID following **R=**, so in this case it would be **1TvYvW-00069r-Au** 2. Using the message ID you copied, run the following command: `exigrep -I -l 1TvYvW-00069r-Au /var/log/exim_mainlog` This will display the full message transaction for the message that bounced: `2013-01-16 14:45:34 cwd=/var/spool/exim 3 args: /usr/sbin/exim -Mc 1TvYvW-00069r-Au 2013-01-16 14:45:34 cwd=/var/spool/exim 7 args: /usr/sbin/exim -t -oem -oi -f <> -E1TvYvW-00069r-Au 2013-01-16 14:45:34 1TvYvW-00069r-Au <= help@example.com H=localhost (secure103.inmotionhosting.com) [127.0.0.1]:40726 P=esmtpa A=courier_login:help@example.com S=1172 id=f25ddf5d4e8c56e73ab82081c9011a34@atomlabs.net T="Test" for no-reply@example.com 2013-01-16 14:45:34 1TvYvW-00069r-Au ** no-reply@example.com R=virtual_aliases: No Such User Here" 2013-01-16 14:45:34 1TvYvW-00069r-Au Completed 2013-01-16 14:45:34 1TvYvW-0006AC-ER <= <> R=1TvYvW-00069r-Au U=mailnull P=local S=2012 T="Mail delivery failed: returning message to sender" for help@example.com 2013-01-16 14:45:34 1TvYvW-0006AC-ER => help R=virtual_user T=virtual_userdelivery 2013-01-16 14:45:34 1TvYvW-0006AC-ER Completed` So in this case we can see the reason the message bounced was **** no-reply@example.com R=virtual_aliases: No Such User Here**. Basically, **help@example.com** had tried to send a message to an email address that didn’t exist so it bounced. 3. You can repeat the sames steps to investigate other bounces that user has been generating. Or an alternative method would be to directly look at the user’s mail with the following commands: `grep "Mail delivery failed" /home/userna5/mail/example.com/help/{cur,new} -R` This gives back something like: `/home/userna5/mail/example.com/help/cur/1358366803.H952383P10133.ecbiz103.inmotionhosting.com,S=2120:2,:Subject: Mail delivery failed: returning message to sender /home/userna5/mail/example.com/help/cur/1358366759.H640077P7532.ecbiz103.inmotionhosting.com,S=2115:2,:Subject: Mail delivery failed: returning message to sender /home/userna5/mail/example.com/help/cur/1358365534.H479296P23705.ecbiz103.inmotionhosting.com,S=2107:2,:Subject: Mail delivery failed: returning message to sender /home/userna5/mail/example.com/help/cur/1358366776.H336048P8578.ecbiz103.inmotionhosting.com,S=2123:2,:Subject: Mail delivery failed: returning message to sender` You can then read one of the bounce backs for further details with this command: `less /home/userna5/mail/example.com/help/cur/1358366776.H336048P8578.ecbiz103.inmotionhosting.com,S=2123:2,` When you’re done looking at the file, you can hit **q** to quit and get back to the command line. You should now understand how to locate users on your server that are generating a large amount of delivery failures, and also how to investigate those bounces to see the root cause of those issues.