If your customers see this error message when attempting to open the widget, it's due to one of the following reasons:
1- Your business' "Enable online booking" setting is disabled.
To activate it, go to "My Business" tab > Booking rules > Enable online booking
2- The hosting region set in your widget's head tag script is wrong.
Your hosting region is determined by the ending of your Booxi account URL. If it ends with ".com", your hosting region is North America. If it ends with ".eu", your hosting region is Europe. As such, you must ensure that the URL included in your widget's head tag script matches your hosting region; see below for reference:
North America (booking widget v3):
<script src="https://www.booxi.com/booknow/booknow.js" async=""></script>
Europe (booking widget v3):
<scriptsrc="https://www.booxi.eu/booknow/booknow.js"async=""></script>