Hi,
Thanks for your answer.
I tried it again.
First when I try to stop the plugin before deleting it I get this error:
Fatal error: Call to a member function bind_param() on boolean in /…/wp-content/plugins/wordfence/lib/wfConfig.php on line 441
So I deleted the plugin folder, all the database you told me (20), and some files that appeared to be related to the plugin.
I re-installed it from the online plugin source, and I still have the same problem. Asking me to insert my email (what I just did) and I can’t scan.
Thanks for your help.