If you run Webex Teams – i.e. http://teams.webex.com – in Firefox and join a video meeting, you might see the error

Could not acquire local media. Please check your settings.

This probably means that support for the H264 video format is missing.

Go to “about:config” and search for

media.gmp-gmpopenh264.enabled

and set it to “true”.

Restart Firefox, and go to “about:addons”, click “Plugins”.

The plugin “OpenH264 Video Codec provided by Cisco Systems, Inc.” should now be installed, and video calls in the Webex web client should now work.