Tagging florentlb as have seen a similar post resolved by you.
Hello Friends,
M Trying to update the records in salesforce schema, using the salesforce activity.
Requirement is to match the key between two systems sachems and update a column ([Contact/Email_Opt_Out_Date_Time__c]) in SF schema.
Getting this error in the salesforce activity.
02/10/2017 17:48:42 sfdcWorkflow processed: 0, inserted: 0, updated: 0, rejected: 0, deleted: 0, ignored: 0.
02/10/2017 17:48:42 sfdcWorkflow -53
02/10/2017 17:48:42 sfdcWorkflow A remote key must be defined on a remote field and a local field. A local change date must be defined on a remote field an a local field.
Under the mapping area, I have defined the property as Unique Remote key, Remote modification date, Unique Local key, Reconciliation Key as in the screen shot.

Is there anything I am missing to add or doing incorrectly?