If the Dubb Icon is not showing up within Linkedin, or is not responsive when you click it, you will need to make sure you have the Dubb Chrome Extension Installed (https://chrome.google.com/webstore/detail/dubb-screen-and-webcam-vi/comhknhgkhbecfolehchaemllofaeppb?hl=en)

You will also need to make sure you are logged into the Dubb Chrome Extension, click on the extension and log in.
If you are using any other extension or program that interacts with Linkedin, this will likely cause the Dubb/Linkedin integration to be unresponsive.