Marvin's calendar sync is still in beta and you may run into some issues while getting setup and syncing your calendar.
Help! I can't setup or sync from the desktop apps
Calendar sync currently isn't possible from the desktop or mobile app. We will address this in a future update! Make sure you set up and sync from the web apps for now.
Help! I can't add my google calendar - it fails to authorize
Normally when you setup a google calendar, a popup window will appear asking for permission to access your google account. If you don't see this popup window, be sure that you aren't using popup/ad blockers or any other privacy browser extensions on app.amazingmarvin. Firefox, for example, has a built-in popup blocker that you can disable like so:
Help! I'm asked to give permission several times each time I sync
Sorry :(. This is a known issue and will be solved in a future update. For many users this doesn't occur, and we suspect that it only happens when you've synced a calendar from your non-primary google account.