Dynamics CRM 2013 Email Router integration getting 401 unauthorized access for outward email.

Hi CRMers,

We configured CRM 2013 on-premise to integrate with Exchange server (Online) using Email Router. 

We have 4 organizations. 

For Organization1 we successfully integrated CRM with Exchange online. In Email Router we able to do LoadData while testing get success message for outward.

For Organization2 also we use same configuration as used in Organization 1. In Email Router we able to do LoadData also but while testing failed for outward message. getting 401 not authorized error message. 

we used same users for both Organizaiton1 and Organization2 for email integration.