Any changes I make within aCalendar (e.g. adding an event, changing the calendar for an event, adding or deleting a calendar) aren't reflected within the local Google Calendar app or from the Google Calendar website. The changes may be reflected in other calendar apps on the same device (e.g. Business Calendar). Moreover, opening one of these other calendar apps may cause the changes to propagate to the local Google Calendar app and the Google Calendar website. Within aCalendar's "Manage calendars" screen, the Google Calendar account has "io-error" next to it.

How can I get aCalendar to synchronize its changes?

System info:
LG V20
Android Oreo 8.0.0
Google Calendar 6.0.56
aCalendar 2.2.7