I've been using the Chrome plugin for Mac with no problems for a while, but recently switched to Firefox for Mac. When I click the orange button to display the list of tasks the window opens but there is an error that reads:
"The page isn't redirecting properly" and the URL it is trying to get to is:
It sounds like you have another plugin that is interfering with ours, or perhaps it is one of your security or privacy settings that is preventing cookies from working properly. If you could create a support ticket and attach a screenshot of the error, that might give us a clue.