Conferencing Attendant could not negotiate TLS and failed to establish a SIP connection. Reason=%1. Front End=%2. Cause: ...

Lync Server 2013

Conferencing Attendant could not negotiate TLS and failed to establish a SIP connection.

Reason=%1. Front End=%2.
Cause: This issue may occur due to TLS certificates on the Microsoft Lync Server 2013 Front End and the Conferencing Attendant being expired, or not in sync.
Resolution:
Check and resolve certificate issues, mismatches between the Microsoft Lync Server 2013 Front End and Conferencing Attendant to restore connectivity.

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