Hi Andie,
If you are using ERMS, you can debug using transaction CRM_ERMS_LOGGING. You can check the details of the work item of type TS00207915 Rule Execution and note the document ID, and then in transaction CRM_ERMS_LOGGING, enter the service manager profile used and the document ID you find in the work item, then you can set breakpoints and debug as usual.
Regards
Abby Ding