pmbs on "[Plugin: All-in-One Event Calendar] Switching month doesn't work, stuck on loading wheel"

When viewing the calendar, switching months takes two minutes of loading time. Either the last or the upcoming month, the calendar is stuck on the "spinning loading wheel" for about two minutes or more, before the next month shows up.

This problem recently occured. Using version 1.10.11 of the plugin.

https://wordpress.org/plugins/all-in-one-event-calendar/