After updating mac OS to Yosemite, access to Adobe Connect may be buggy. Attempts to access an Adobe Connect meeting via both Firefox and Safari may time out when trying to load the room. When using the add-in instead, it may load, but appear extremely buggy, flickering on and off, and spontaneously quitting and reopening the room.
Go into Preferences>Security either in Safari or Firefox, navigate to the Adobe Connect room's URL, and allow both "www.adobe.com" and the add-in to "Run in unsafe mode," available via the dropdown menu there. This should resolve the issue.