Updated: As noted by Google, Google Calendar has now come back online. "The problem with Google Calendar should be resolved. We apologize for the inconvenience and thank you for your patience and continued support. Please rest assured that system reliability is a top priority at Google, and we are making continuous improvements to make our systems better."
If you're a heavy Google Calendar user, you may have noticed the website is currently down right now and producing different error messages. Google has noted via their G Suite Status dashboard they are currently investigating and will provide further information soon.
We're investigating reports of an issue with Google Calendar. We will provide more information shortly. The affected users are unable to access Google Calendar.
While the website is down, it does seem as though the Google Calendar app and apps that integrate with the Google Calendar are working perfectly fine for local content though synching might be affected. When things get back to working order, we'll be sure to update the post.