One common bounced back email error message when sending email is: 550 Mailbox quota exceeded. This means that the recipient was not able to accept the message because their inbox was full.

What if the email account over quota is not mine?

Sometimes when you send an email, you will get a bounceback email with the Quota Exceeded error.  This means that it's not your inbox that's full, but the person you're sending the email to. Try contacting the person by another method and let them know their inbox is full. You can also try again later to see if the email address owner has corrected the issue.

What if the email account over quota is hosted on my cPanel?

If your email address has used the allowed quota, there are a few ways to correct this.  First, you could simply delete some of your emails. Deleting emails in your email client will remove them from the server and lower the space used. If you have any emails with large attachments, deleting those will free up space. You could also raise the quota of your mailbox.

How to Raise your Mailbox quota:

1. login to your cPanel.
2. Next, navigate to the Email Accounts section:

   

3. If any of your email accounts are over quota, they will show in red as shown below:

   

4. To raise the quota, click on "Change Quota" under actions and the following will appear:

   

5. Raise the number in the "Mailbox Quota" field and click Change Quota.  Now, as you can see the quota has raised and the address no longer shows as red:

   

   You can use this method to raise the quota on any email account. If any inboxes are close to full, you can raise the quota to avoid a future issue.

How do I set a reminder for when my Inbox is near the Quota?

In cPanel, you can set an email reminder when your email address is near your quota.

1. Log into your cPanel.
2. Click on Update Contact Info in the Prefences section:

   

3. Put in your email address, and make sure the third box is checked:

   

4. Click Save. Now you will be notified when your inbox's almost full. 

Congratulations, now you know how to correct the 550 Mailbox Quota Exceeded error!