UCWA encounters an unhandled exception "System.ArgumentNullException" in Lync Server 2013 Content provided by Microsoft Applies to: Lync Server 2013 Select Product Version All Products To fix this issue, install the July 2018 cumulative update 5.0.8308.1001 for Lync Server 2013, Web Components Server. Last Updated: Jul 9, 2018 Can't find what you're looking for? Search No results 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.