site Editor can’t save changes, can’t create new template

Hi,

I made a Twenty Three child theme.

When I make a change on a template in the site Editor, I click Save, It displays “template saved”, but when I reload the list of templates, I see that the change was not saved (same on front-end).

When I click Create new template, it says “template was created”, but nothing appears in my template list…

Then I duplicated my child theme, to make a new (not a child) theme. I deleted the original 23 theme. But the issue is still the same.

Thanks for your help