We have a lync enterprise 2010 deployment.

Only one part fails:

Additional Details
Couldn't sign in. Error: Error Message: The endpoint was unable to register. See the ErrorCode for specific reason..
Error Type: RegisterException.
Deregister Reason: None.
Response Code: 504.
Response Text: Server time-out.

• Edited by iconoclast88 Monday, March 04, 2013 10:07 PM

Hi,

Where do you get this error message?

Looks like the Lync client can't log in. Please check the Lync FE server services are started. Please try to restart the Lync FE server then check the issue again.

That has been done.

Internally, I can connect, but when going through externally, through edge server is when I get the error message.

On the Front end server lync log, I get this:

event id: 25015

Source: mediation server

The A/V Authentication service returned invalid response. connections that require firewall traversal will not be successful.

Response code: 504

Response text: server time-out

Cause: Either the A/V Authentication service is not running or unreachable.

I have made sure that the service is running.

Co-located mediation role on front end server.

• Marked as answer by iconoclast88 Friday, March 08, 2013 6:45 PM

Found that the issue was I didn't have edgepool.domain.com configured correctly, pointed to wrong IP.

doing that fixed the initial error.