I'm having the same problem - the add-in will load, but the button to post to evernote is stuck on "Loading..." I can access it from the web client Outlook, but the thick client Mac version is stuck on Loading. I have tried restarting Outlook. Logging out and back-in to the Evernote Add-In. Removing the Add-in and re-installing it. Connecting to an alternate network (via mobile hotspot vs hardwired). None of the above resolved my issue.