O365 Add Fail - TaskException: There are multiple recipients matching identity

As the name suggests, this error will occur if an O365 ADD conflicts with an existing O365 contact. While this may in fact indicate a valid issue, if it’s a synced object, it may be due to a known bug in pre-v4.1 installations.

Example of error:

Add Error    | TaskException: There are multiple recipients matching identity 
"DianeMiller@domain.com".  Please specify a unique value.

Add Fail       | DianeMiller@domain.com

If you are running any version prior to v4.1 AND there IS an existing Destination contact (previously synced by UnitySync), this error may be caused by a known issue.

This has been fixed in v4.1. It is recommended you upgrade to the latest version of UnitySync to resolve this issue.