The widget’s settings are wrong

Code: invalid_config

The widget could not read its settings: an attribute of the code on the page is wrong, or the server sent no settings for this key.

How to fix it

Take the code from the On your website tab and replace the code on the page with it, unchanged.
If you added a data-config attribute, check that it holds valid JSON in single quotes.
Publish the widget again: Online booking, Appearance, Save and publish.

The message in the browser console names the value that is wrong.