Symptoms
When the Skype for Business for Mac client signs in, the application reports the client’s location to Unified Communications Web API (UCWA). The location is then used to determine the E911 (emergency) call location. Because of a regression caused by changes for external access and Location-Based Routing (LBR) in earlier versions, the E911 location is not retrieved when the location policy is specified on the subnet instead of on the user, leaving the E911 location unavailable when you make emergency calls.
Resolution
To resolve this issue, install the July 2018 cumulative update 6.0.9319.534 for Skype for Business Server 2015, Web Components Server.
