We have a Lync Enterprise Edition installed with a Edge server in the DMZ, we had an internal CA certificate for the external access interface while we waited for the public certificate and everithing was working fine. The only downside with this workaround
was that only the users that have the Root CA could connect from the outside.
When the public certificate arrived we assigned it to the external interface and rigth afterwards the users connecting from the outside received this message upon connecting
so you have purshased a public Certificate for the edge server,
Does the exchange Certificate that is used for Client Access Services publishing is also from a public CA ?
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Please check you have install the public certificate correctly,if you are using Godaddy certificate please make sure that you have the Intermediate certificate(s) correctly installed in your environment.Details you can check
BTW,is there any error message about "Microsoft Lync MAPI COM Server“ (Mostly caused by using UAG as the reverse proxy server which is not supported by Microsoft).