If your microphone or camera is not working in Blackboard (or Canvas) please check to make sure they are enabled in the Chrome browser. 

If it was mistakenly blocked, your can change that by going to the padlock symbol next to the URL (1), (Note: you must be on the page that you wish this change to take effect on. So for Blackboard you must be on a page with "us.bbcollab.com" in the URL). 

In the boxes next to Camera and Microphone where is says Blocked, use the drop downs to Change the selection to Allow (2). And then click the X in that popup box and reload/refresh the Blackboard page. 

If you don't see Camera or Microphone as a selection after clicking on the padlock symbol you will need to open Site settings (3) in that menu: 

On the following page you will need to change the setting for Camera and Microphone to Allow from Ask (or Blocked). 

Then close the Settings window from the tab: 

You will have to reload/refresh the Blackboard page for those changes to take effect.