You can use a configurable setting to allow automatic closure of CA SDM tickets. When a ticket is set to a Resolved status, the ticket is automatically closed in the number of business hours specified. The Auto Close activity notification sent to the end user displays the number of business hours before the ticket is closed. You can configure business hours for each tenant. If the status is changed before the configurable number of hours ends, the ticket closure is canceled.
What are the possible root causes for Auto Close feature not triggering ?
CA Service Desk - All Supported versions.
See this section of the documentation for more details: Automatic Closure of Tickets