Internal Server Error: Cannot access the calendar you requested

Question:
I frequently get an "Internal Server Error Error G o o g l e Error Cannot access the calendar you requested." What happens?

Answer:
This is an issue at Google's server. When you get this error message on the gadget, you also experience the same at the original Google Calendar UI. If you log in to Google Calendar UI and refresh your browser, you can see something like this:

Tip:
Do nothing, the error usually goes away in a few minutes.