Cannot remove threat Mal/obfJS-B

Hello

I received this error message Received message "The threat cannot be cleaned up. Please click the threat name above for manual cleanup instructions - Mal/obfJS-B" in my Quarantine Manager.

I am unable to access the Clean Up Threat button so I ran the Sophos Full Scan and it is still listed in the Quarantine Manager.  Can someone tell me how to remove this file from my Mac Book please. Thanks