"403 Forbidden" issue on account creation page

[PCLINE]

welcome
Greetings to all forum members

A few days ago, I discovered a problem on my website.
On the Create New Account page:
https://www.pcline.dz/fr/connexion?create_account=1
- When writing correct data and pressing the Register button, the page will reload without creating the new account.
- When writing wrong data, such as putting numbers in the name field, a "403 Forbidden" error page appears like this one:

Note:
- When creating an account with this "Notification Pop up" module on the home page. Registration is done correctly and without problems.
- When creating an account on the order page, if the data is correct, the account is created correctly and without problems. However, if the data is wrong, the "403 Forbidden" error page appears.

I hope to find someone who helps me solve this problem, the problem worries me a lot.