RAR - Mitigation

Hi Experts,

How can I unassign a mitigating control from a role (this is a test role; not assigned to a user)?

In RAR, under Mitigation > Mitigated Roles, I clicked on Delete and received the following error message:

com.virsa.cc.rulearchitect.dao.DAOException: Error:Sending failed; nested exception is: javax.mail.MessagingException: 501 5.1.8 Domain of sender address does not exist

I intentionally didn't configure the workflow under Configuration > Workflow by setting all values to "No"

Any advice would be much appreciated.

Thanks!