Reference: https://www.cisco.com/c/en/us/td/ docs/security/esa/esa11-1/user_guide
/b_ESA_Admin_Guide_11_1/b_ESA_Admin_Guide_11_1_chapter_0100010.
html#task_9F07A032042F48C6AEDB69D325CD3C5F
To address this issue, the administrator should roll back to a previous version of the engine from the Services Overview page on Cisco ESA. This will restore the functionality of graymail service and prevent it from crashing.
The Services Overview page allows the administrator to view and manage various services on Cisco ESA, such as antivirus, outbreak filters, graymail, etc., and perform actions such as enable/disable, update, or roll back.
The other options are not valid solutions to address this issue, because they do not allow the administrator to roll back to a previous version of the engine for graymail service.
References: User Guide for AsyncOS 15.0 for Cisco Secure Email Gateway , page 6-18 and page 6-19.