UCWA may crash when parsing the ms-trunking-peer header in Skype for Business Server 2015 Content provided by Microsoft Applies to: Skype for Business Server 2015 Select Product Version All Products Unified Communications Web API (UCWA) crashes because of an invalid value in the ms-trunking-peer header in Skype for Business Server 2015. Resolution To fix this issue, install the February 2017 cumulative update 6.0.9319.277 for Skype for Business Server 2015, Web Components Server. Last Updated: Feb 13, 2017 Did this solve your problem? Yes No Tell us what we can do to improve the article Submit Thanks! Your feedback will help us improve the support experience.