thank you for you reply. I looked at my cake log file here are the error messages I got:
2020-03-03 08:27:24 Error:
[Cake\Http\Exception\InvalidCsrfTokenException] CSRF token mismatch. (/appli/projects/dr-lorraine/apache_2.4/htdocs/dr-lorraine/eprestaLorraine/vendor/cakephp/cakephp/src/Http/Middleware/CsrfProtectionMiddleware.php:232) and
#9 /appli/projects/dr-lorraine/apache_2.4/htdocs/dr-lorraine/eprestaLorraine/vendor/cakephp/cakephp/src/Http/Runner.php(65): Cake\Error\Middleware\ErrorHandlerMiddleware->__invoke(Object(Cake\Http\ServerRequest), Object(Cake\Http\Response), Object(Cake\Http\Runner))
I don’t understand this error.