Make sure your Flash settings are to “Allow” and “Remember” Collaborate’s access to your camera and mic
If you don't have a mic installed, or it's been disabled due to security, you may see this message -->
Click the almost-invisible X in the upper right corner to click past the message and continue to join the session.
If you can join the session on your computer, but don't have a mic installed, you can still phone into the session using the "Session Menu" in the upper left of the session, and clicking on "Use your phone for audio."
You will be given a phone number to call and unique pin that will that attach your phone to your computer Ultra session identity.
You may get a message like this, that tells you that you need to install Flash. That may not necessarily be true. It may just need to be enabled.
If you're using Explorer, try this first. Go to Settings in Explorer > Manage Add-Ons.
In the Manage Add-Ons window, make sure you're in Toolbars and Extensions, then look for Shockwave Flash Player. If it's disabled, click the button at the bottom to enable.
If it's not present and you are able to download software on your computer, go to https://get.adobe.com/shockwave/otherversions/ to install.