Hi DanielR79,

Is your Lync server a Standard Edition or an Enterprise Edition?

If it is a Standard Edition, the URL of internal web service should be consistent with FQDN.

If it is an Enterprise Edition, when change the URL of internal web service, you should create another DNS record to it.

Please check if the SIP traffic and HTTP traffic are unblocked.

Here is blog about the process of Lync 2010 client to request the certificate may help you:

http://blogs.technet.com/b/nexthop/archive/2012/11/28/lync-2010-client-authentication.aspx

Best Regards,

Eason Huang

Hi, we have just migrated from Lync 2010 to Lync 2013 and are having a problem, The Lync 2013 clients dosent seem to be able to request the user Communication certificate. the 2010 client are able to get the certificate from the new pool and login without any problem and if i use the 2013 client on a computer that already had the 2010 client so the certificate is already there then it works, but a clean install 2013 dont want to get the certificate..

any ideas on what i could try to get it to work ?

BR

Daniel