Thank you for the insight.
The running template is Lovecraft, as on the site that works fine (www.vivremieux.org). I have tried 3 other templates (including the default Twenty series).
I have changed the display type and changed it back – it is the same setting as on the site that works fine.
I have created a 2nd dedicated API ; I tried it ‘unrestricted’.
It seems to me that all settings are the same between http://www.vivremieux.org (where the extension works fine) and http://www.biodanza-occitanie.org (where the problem occurs).
I am thinking to uninstall et reinstall it. I guess I’ll have to save my few coming events and paste them back one by one…?
Unless someone has an illumination about what I am doing wrong or what went wrong in the system ??
Thank you