Had an issue today where i couldn't send an IM to a federated contact from OWA on Exchange Online and Onprem 2013. If a federated contact sent me an IM i received the IM in OWA, clicked accept and i could send and receive IMs successfully. but If i initiated the conversion to the federated … Continue reading Lync 2013 issue sending IM to external / federated contacts from OWA in Exchange 2013