When running Microsoft Lync, Lync will make itself the default handler for tel: uris. When using the click to dial web browser extensions, this causes Lync to try and handle the phone number instead of the .net client. Deploying this Addin will make sure that the client will handle the phone number.
Download the release zip file from the releases tab in GitHub and unzip this file to your C:\Program Files (x86)\Interactive Intelligence\ICUserApps\AddIns directory. If you don’t have a AddIns directory, just create one. Then exit out of your client and restart it.