In this case concerned that the plug-in prompt failed, to isolate if the problem is related to your browser, you can try to remove the plug-in completely and then re-start your Mac machine, after that if convenient you can try to change another browser likeĬhrome or FireFox etc and then open it with InPrivate Mode to launch the join meeting link ( you may receive an email), and when it prompt you to install the plug-in again, try it and then see if the plug-in can work normally. And you also got a prompt about the plug-in failed.

Based on your description, you are a normal Skype user but not using Skype for Business, and when you joined a skype for business meeting via Skype for Business Web/Meeting App ( just the plug-in you used), and then you found you can only chat but no screensharingĪnd audio.