Exim automatically removes frozen emails on a cPanel server after 5 days. If you want to increase or decrease this number, you can do so.
Official Exim documentation is available at: Main configuration
- Go to "Home / Service Configuration / Exim Configuration Manager"
- Click the Advanced Editor tab
- Search for timeout_frozen_after until the setting box is found.
- Change the value as needed. Example: 1d or 24h
- Scroll down and click save
Please note the following from the Exim documentation. "The default value of zero means no timeouts; with this setting, frozen messages remain in the queue forever (except for any frozen bounce messages that are released by ignore_bounce_errors_after)."