- Time-skew occurs between the Lync client and Exchange Client Access Server. Therefore, the Lync client cannot discover Exchange Web services automatically.
- The EWS integration encounters an incorrect endpoint.
- Lync client is not synchronized with a time server.
- The certificate is expired or not trusted. Or the federation trust is configured incorrectly.
- The CustomBinding class is configured in the "web.config" file on the Lync client-side.
Article ID: 2957351 - Last Review: 25 Apr 2014 - Revision: 1