Summary
This update adds a flag (allowCrossDomainRequests="true") to the Web.config file in Microsoft Skype for Business Server 2015 to allow the Join Launcher feature to accept anonymous meeting join requests that are across-domain from the Web SDK.
Resolution
To enable this feature, install the February 2017 cumulative update 6.0.9319.277 for Skype for Business Server 2015, Web Components Server.