display calendar on website

Hi,

Since a few weeks I noticed that the calendar is only showing on the frontend of my website when I am logged in. When logged out it says it cannot retrieve data.

What have I missed in the settings to fix this?

I have imported a Google calendar feed to display my events.

Please advise how to fix this.

Thx and regards,
Sandra

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