Updated: 11 October 2026 · Applies to: cPanel & WHM 138 (Jupiter theme)
A mailbox quota limits how much mail one account can store. When the mailbox is full, new messages bounce back to the sender.
Steps
- Log in to cPanel (for example at
https://yourdomain.com:2083, or from the Ucartz client area). - Open Email › Email Accounts.
- Click Manage next to the address.
- Under Storage, set Allocated Storage Space to a new size in MB, or choose Unlimited.
- Click Update Email Settings.
The Storage: Used / Allocated / % column in the account list shows how full each mailbox is.
Tip: To free space instead, delete old messages in Webmail or with Email › Email Disk Usage, which can remove messages older than a number of days from a folder.
