Hi @madicav82 : This error will happen if you fire an action at Calendar Grid Pro, but Calendar Grid Pro is not yet initialized. You can’t (for example) fire an action at Calendar Grid Pro on Bubble’s “Page Loaded” event.
Calendar Grid Pro relies on a rather large library and loading of this library is done asynchronously and in a non-render-blocking way. So, by design, Calendar Grid Pro is never assuredly initialized until a short time after the Page Loaded event.
So, if you want to fire events at Calendar Grid Pro at the first possible moment when the plugin is initialized, you use the “Calendar Initialized” event.
Instead of doing such things on “Page Loaded”, do them instead on Calendar Grid Pro’s “Calendar Initialized” event.
For a discussion of why my plugins work this way, see my video here: Parallels: Date and Date Range Transformer (Now with Video Demos! 
) - #10 by keith
ASIDE: Note that there’s no need to fire Jump to Today at Calendar Grid Pro. If you don’t supply a starting date for the calendar, it displays the month containing “today” by default. Similarly, there’s no need to fire “Clear Dates” at CG Pro when it’s first initialized, as there’s no selection to clear.
Best Regards,
Keith