If your emails have suddenly stopped going out and you receive a bounce mentioning "Max defers and failures", don't panic. It's an automatic protection from our server to safeguard your domain's reputation — let's identify the cause and get it working again.
What does this error really mean?
To prevent your domain from ending up on "blacklists", the server monitors how many failed emails you send per hour. If you try to send messages to many addresses that don't exist or that reject you, the system temporarily blocks outgoing email to protect you.
It's normal to be confused at first, but you'll see that finding the origin is fairly straightforward.
Action Guide: How to fix it step by step
Depending on your control panel, follow these steps to see what's stopping your emails:
In cPanel
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Find the "Track Delivery" tool: Type "Track" in the main cPanel search bar and click on it.
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Filter the results: You'll see a table with all send attempts. Look at those with a red or yellow circle.
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Read the error column: Click on the information icon (the small blue envelope or "i") to the right of a failed email. There you'll see why it bounced (example: "User not found" or "Inbox full").
In DirectAdmin
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Go to "E-mail Summary": You'll find it in the Email tools section.
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Review "Sent" vs "Failures": If you see a specific user has hundreds of failures, that's the origin of the problem.
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Check the "Mail Queue": If there are emails you didn't write, an account is likely sending spam without your permission.
How do I fix it right now?
Once you've identified the problem, you have three paths depending on what you found:
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If it was a one-time error: If you tried to send a newsletter to an old list, simply stop sending emails for an hour. The block clears itself once that time passes.
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If an account is sending emails you don't recognize: Change the password of that email account immediately from your panel. You'll see a "Change password" button next to the affected account — use a strong combination.
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If it's a form on your website: Make sure your contact forms have CAPTCHA. If they don't, bots can use them to send garbage, causing this block.
Bacan Pro-Tip
Most of these blocks happen because we use old contact lists. Before doing a bulk send, run your list through an email validator. This will remove addresses that no longer exist and prevent you from hitting the hourly failure limit. Your sender reputation will thank you!
To keep in mind:
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Wait 60 minutes: The block is automatic and clears itself every hour if you stop trying to send failed emails.
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Clean your lists: Don't send emails to accounts that have previously bounced.
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Check your passwords: If the error persists without you doing anything, change your email passwords — it's the most effective security measure.