Password reset 504 Gateway TimeOut - Plesk maybe ?

[Todixys]

Hello, 

When i try to do a password reset, i have a reload loop and a 504 Gateway Error, nothing in error log etc... Same problem when i try to edit mail setting (example: when i try to switch smtp to phpmail)

One error on system log  : 

Password Reset Request Failed: Email Sending Failed: SMTP connect() failed. https://github.com/PHPMailer/PHPMailer/wiki/Troubleshooting - User ID: 141

Video : 

PHP 7.4.16