danvratil
commented
3 years ago Facebook has completely removed support for the "Old UI" some time ago and so was gone the way to retrieve the calendars. It's back now (maybe has been back for a while, I mostly gave up on the app after the UI update). I should be able to solve that in next update - details in #85
Mine is just stuck on 'retrieving calendars' until it eventually just stops with no signs, or I forget to keep the screen lit and it has just given up when I touch the phone again. Hasn't done one successful sync.