If you are wondering why the Lync or Skype for Business sign-in address is not auto-populated for Lync Online users signing in on a domain joined machine, chances are that either of the following 2 Active Directory attributes are not populated:
To edit AD attributes from AD Users and Computers, first make sure you have enabled “Advanced Features”:
If you have deployed the Active Directory schema extensions required for Skype for Business or Lync on premises, then you can use the msRTCSIP-PrimaryUserAddress attribute. In many cases if you are using Office 365 Lync Online this will not be the case, so you will use the next option rather than extending the schema for this specific purpose.
If msRTCSIP-PrimaryUserAddress is not available to you, then you can add a sip record to the proxy addresses list in the following format:
Just 2 notes:
1) the proxyaddress screenshot is wrong (its the same as the primaryaddress screenshot)
2) under what circumstances do I have to use option2 instead of option1? When AD is not / can not schema updated, or something else? Some words about that in the post would be great. There is nothing worse, than a list of options I have to choose from, but I am not advised at all about the pros and cons of each path.
Thanks for pointing out that mistake, all sorted.
Its not so much that there are pros and cons – If you are online only then its likely you would not have the Active Directory schema extensions required when you install Lync/Skype4B on premises. In this case you only have the option to use proxyaddresses. If the schema had been extended in the past you have the option to use either, but I certainly wouldn’t go extending the schema for this specific purpose.