Domain has exceeded the max defers and failures per hour
This article will explain why you would receive a notification like "Domain has exceeded the max defers and failures per hour" cPanel.
What is causing the domain to exceed 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 for having the email message bounce back to you and correct the mistake before trying to resend the message again.
Bounce back messages are very important, but about 90% of users do not pay enough attention to read them. They either retry sending the failed message several times or use email software that will keep resending the message countless of times. Please do not do that! Try not to rely blindly on email software, because they are really dumb. By now, you are probably asking yourself... "A bunch of bounced back email messages, So what? What is the big deal?" Right? Right... Keep reading, because it gets interesting!
Failed email messages will exhaust the receiving sever, as a result the receiving server will consider the email messages received to be a waste of its resources. It will eventually block emails received from your domain or IP address temporarily, or even worse. It could 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, because Email providers use RBLs to assess the reputation of all incoming email messages. There is a high chance no one will want to receive email messages from you, due to the bad reputation for sending bad email messages. It will be so difficult to send email. This situation will be harder to fix, so it is always better to prevent this from happening in the first place.
A Funny Example About Mr. Clever!
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" but 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?
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“. The email hosting provider has decided to defer your messages or block email messages from your domain or IP address temporarily. Realtime Blackhole List will blacklist you without this protective measure, but you knew that already. Right?
All you have to do is find the source triggering this protective measure 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, change your hosting provider. Greens247 is the recommended web hosting provider, they have fast website hosting and excellent customer support. Contact Greens247 Customer support, to get them to help you fix the problem.
A cPanel / WHM Administrator can lift this limitation temporarily buy typing the following in terminal.
rm -f /var/cpanel/email_send_limits/max_deferfail_domain.com
Replace "domain.com" above by the impacted domain.
Why the server defers 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. A domain will not be able to send outgoing email messages. This is temporarily due to exceeding the maximum failed or deferred message percentage. - The default value for this setting is 5 emails per domain per hour, so five failed or deferred messages trigger the protection in addition to the failed or deferred message percentage above.
Reaching this limit will cause the user to be notified with the following;
"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?
- Verify that you are sending to the correct email address, because it is highly likely to be a spelling error.
- 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.
- Protect your devices against viruses and malware. Malware can gain control over your mail software to send spam and harmful malicious messages to other users.
- If you plan to send email from a website, do not use the same domain. An exploited or hacked website, may send spam.
- Deferred email messages are the result of sending an email message to address or domain that has reached it's disk quota.
