Disk quota exceeded: mailbox is full


Email fails with the following error message.

Subject: Mail delivery failed: returning message to sender

'mailbox is full: retry timeout exceeded' 

Reasons for the error message:

Following are the possible reasons for the error message:

1. The disk quota exceeded for the email account.

2. Disk quota for the particular domain exceeded.


In order to fix the issue, either clear out the unwanted/old emails or increase the quota for the email account.

Steps to increase the quota for an email account:

1. Login to the cPanel of the domain.


2. Click on "Email Accounts" under "Mail" section.

In the following page, we can see the list of email accounts existing under that domain. Increase the quota for the email account by clicking "Change Quota" and changing it to the required value.

If the disk quota of the email account is not causing the issue then the quota limit for the domain might be exceeded.

Different ways to check the disk usage by a domain:

1. Login to the cPanel of the domain.

2. In the home page, under stats section we can see the disk usage by the domain.


2. Click on the "Disk Space Usage" under "Files". In the following page you can see the overview of the disk space used by your account. Either you can delete the unwanted files or you can increase the quota of the domain.

Steps to increase the quota for a domain:

1. Login to the reseller WHM panel.

2. Click on "Modify accounts" under "Account Functions".

3. In the following window, select the domain for which you need to change the quota and click "Modify".

4. Change the value of "Disk Quota" to the required one and click "Save".
  • 2 Users Found This Useful
Was this answer helpful?

Related Articles

Custom php settings when you enable Fast-CGI

When you enable fast-cgi, there should be a custom php.ini in the cgi-bin folder of the account.*...

Can I edit DNS records from my CPanel?

You can edit DNS records from your CPanel by following the instructions in the two CPanel...

CentOS - Hostname Change

Hostname Change There are 4 steps in a hostname change, luckily all the steps are easy....

What Is A Reverse PTR Record?

PTR record or more appropriately a reverse PTR record is a process of resolving an IP address to...

Why Do You Need A Reverse PTR Record?

The most common use for looking up a PTR record is done by spam filters. Concept behind this idea...