Updated: 3 November 2026 · Applies to: WHM, cPanel's Exim-based mail limits
cPanel's hourly email limiter caps how many messages a domain can send per hour. Once a domain hits its limit, it is blocked from sending further mail until the next hour, and the sender gets bounce messages for anything they try to send in the meantime. Raise or lower this limit per account from WHM.
From the WHM interface
- Log in to WHM.
- Under Account Functions, open Modify an Account.
- Select the account and click Modify.
- Find Maximum Hourly Email by Domain Relayed in the account's settings. By default it is set to Unlimited.
- Switch it to the numeric option and enter the limit you want.
- Save.
Directly on the server
If you need to change it without going through WHM, for example from a script, edit the account's own config file:
vi /var/cpanel/users/username
Change the value of MAX_EMAIL_PER_HOUR to the new limit and save the file.
Then rebuild the threshold files Exim actually reads to enforce the limit:
/usr/local/cpanel/scripts/updateuserdomains
The change in the user file alone does not take effect until this script runs; WHM's own interface runs it for you automatically, which is why the backend method needs this extra step.
Unblocking a domain that has already been blocked for exceeding its limit
Check /var/cpanel/email_send_limits/ for a file named after the affected domain, for example max_deferfail_example.com. Removing that file clears the block.
