Can’t use Ajax with Solid Security ?

Hello,

I’ve found a problem on my website. In an administration page that I made, I’m trying to do an Ajax resquest but it seems that Solid Security block it.

The resquest works well with Solid Security disabled or with Workfence. But I have a 403 Forbidden error on the console when I try to access to a different file

Here is my code :

jQuery(document).ready(function($) {
$("#tirage_gagnant").submit(function(e) {
e.preventDefault(); // Empêche le formulaire de se soumettre normalement

var formData = $(this).serialize(); // Récupère les données du formulaire

// console.log(formData);

$.ajax({
type: "POST",
url: "/wp-content/themes/mytheme/myfile.php", 
data: formData,
beforeSend: function() {
$("#liste_resultats").html("Chargement en cours...");
},
success: function(response) {
$("#titre_resultats").html('<h2>Liste des personnes</h2>');
$("#liste_resultats").html(response); 
},
error: function(xhr, textStatus, errorThrown) {
alert("Une erreur s'est produite lors de l'envoi des données.");
}
});
});
});

I’ve got the alert showing when I’m sending the request, and the console show me this :

POST https://mywebsite.fr/wp-content/themes/mytheme/myfile.php 403 (Forbidden)
send @ load-scripts.php?c=0&load%5Bchunk_0%5D=jquery-core,jquery-migrate,utils&ver=6.4.2:2
ajax @ load-scripts.php?c=0&load%5Bchunk_0%5D=jquery-core,jquery-migrate,utils&ver=6.4.2:2
(anonymous) @ load-scripts.php?c=0&load%5Bchunk_0%5D=jquery-core,jquery-migrate,utils&ver=6.4.2:5
e. @ load-scripts.php?c=0&load%5Bchunk_0%5D=jquery-core,jquery-migrate,utils&ver=6.4.2:5
(anonymous) @ admin.php?page=tirage-au-sort:249
dispatch @ load-scripts.php?c=0&load%5Bchunk_0%5D=jquery-core,jquery-migrate,utils&ver=6.4.2:2
v.handle @ load-scripts.php?c=0&load%5Bchunk_0%5D=jquery-core,jquery-migrate,utils&ver=6.4.2:2

What can I do to allow ajax on my website (at least in the administration part…) ?

Thanks !

[Edit : XML-RPC is activated, the checkbox “Allow multiple authentication attempts via XML-RPC” is checked and “Default block list” is unchecked].