On Wire for Web (Firefox version 48 and newer):
If screensharing does not work on Firefox, please check that Wire is in the screensharing whitelist:
- Open Firefox and type: "about:config" [Hit Enter]
- Search for "media.getusermedia.screensharing.allowed_domains" and double click it
- Add ",*.wire.com" at the end of the list
- Click OK
If you are still experiencing issues with this, please contact us.