This article will explain why you would receive a notification like "Domain has exceeded the max defers and failures per hour".
The email sent will bounce back to the original sender, because the receiving sever could not find the recipient. Usually you should read the reason why the email has bounced back to you and correct the mistake and retry sending the message again to the correct address. You are probably asking now, why you are being told this example. Well because 90% of users do not read the bounce back message and they either retry sending the failed message several times or use email software that will keep retrying to send the message countless of times. Please do not do that, and do not rely blindly on email software. They are really dumb. So now you are probably asking yourself, "I am sending the message and it is getting bounced back to me, what is the big deal?"
The receiving sever will get tired from your failed email messages, and will consider the email messages to be a waste of its resources. It will eventually block emails received from your domain or IP address temporarily or even worse, it will block your domain and IP address and report them to a Realtime Blackhole List also known as RBL. This is very bad to your domain and IP address reputation, because RBLs are used by many providers. This means there is a high chance no one will want to receive email messages from you. You will be surprised to find bounced email messages from sending email messages to most of your address book. This situation will be hard to reverse, this is because you are now known to have a bad reputation for sending bad email messages. No one would want to receive email messages from you.
Put yourself in the receiving server's shoes. If you were the mail man, and you took an envelope to an address and knocked the door and said "Hey! I got mail for Mr. Clever" An old lady with a stick answers the door and replies to you "Hello there! No Mr. Clever here, you got the wrong address". Would you keep trying to send the envelope to the same house over and over again? Believe me getting hit on the head with a stick by the old lady will be the least of your worries.
How to fix Domain has exceeded the max defers and failures per hour
If you are a cPanel user and you keep receiving email bounce message or notifications like "Domain has exceeded the max defers and failures per hour". You need to start reading those bounce messages and find the reason for these bounce messages. If you are using email software, please make sure you remove this message from your outbox and change the email software settings to reduce the number of retries it will take to send a failed message.
The notification will look something like this “Domain example.com has exceeded the max defers and failures per hour (5/5 (100%)) allowed“. This notification means the sever you are sending email messages from has decided to defer your messages or block email messages from your domain or IP address temporarily to protect you from getting black listed by Realtime Blackhole List as described in the 4th paragraph above. This notification is a good sign, it means there is a fail safe protection is working.
All you have to do is find the source causing this fail safe to get things back to normal again. There are many reasons why the receiving sever would reject the message and bounce it back to you. If you are unable to fix it or find the reason for it, contact Greens247 Customer support. We will help you fix the problem.
A WHM Administrator can lift this limitation temporarily buy typing the following in terminal
rm -f /var/cpanel/email_send_limits/max_deferfail_domain.com
where domain.com is equal to the domain where your messages are defered.
Why the server defer email messages?
Server administrators protect the servers and network from blacklisting by several techniques.
- Limiting outgoing email per hour from each domain.
- Limit the number of unique recipients per hour to trigger potential spammer notification;
The system will send a notification when any email account sends email to more than the specified number of recipients in one hour. Email sent by mailman is exempt from this detection.
- Maximum percentage of failed or deferred messages a domain may send per hour;
The maximum percentage of a domain’s outgoing mail that can consist of failed or deferred messages. Once the domain exceeds this percentage, it is temporarily blocked from sending mail.
- Number of failed or deferred messages a domain may send before protections can be triggered;
When a domain sends this number of failed or deferred messages in an hour, and the “Maximum percentage of failed or deferred messages a domain may send per hour” has also been reached, the domain will be temporarily unable to send outgoing mail.
How to prevent exceeding max defers?
- There is no such email account created on the mail server. Verify that you are sending to the correct email address.
- Read email bounce messages, to correct obvious mistakes.
- Do not use your email address to send marketing emails, use an email marketing agency instead. Customers who send out mass mailings have been triggering this feature, due to the number of bad/undeliverable email addresses on their lists.
- Use a strong email password, if someone gains access to your email address they can use it to send spam.
- Make sure your computer or device is protected against viruses and malware. Malware can gain control over your mail software to send spam and harmful malicious messages to other users.
- Exploited or hacked sites sending out spam emails. If you have a website that is sending email from your main domain. If this website gets hacked, the hacker might send spam from your hacked website.
- The disk quota for the email account/domain has been reached and new messages are being deferred.
Last update: October 1st, 2021