I'm about to update the plugin to the newly-released version today and will let you know if it is resolved. This is from a previous post at: https://premium.wpmudev.org/forums/topic/appointments-gcal-integration-is-not-working#post-471899
After a little research on Google's Calendar API, they have upgraded their most recent (v3) API to using JSON. https://developers.google.com/google-apps/calendar/migration Though the doc says it is backwards compatible... Not sure if this helps...
When filling the info for an Appointment, submission hangs with a never-ending spinner graphic.
I have not gotten a test event in my Calendar, and it was setup just as described.
When trying to access Calendar from the client-side, there is also no response.
Thanks for the help!