Phpmyadmin: reCaptcha not displaying

[acsfer]

Steps to reproduce

1. Enable recaptcha on config.inc.php
2. Display user login page
3. No reCaptcha box displayed
4. SSL enabled Website (https)

Expected behaviour

The box should display to enter the code

Actual behaviour

No box displayed, and after login, we have a message:

Please enter correct captcha!

Server configuration

Operating system: ubuntu 16.04 LTS

Web server: Apache § nGinx

Database: MariaDB 10.1

PHP version: 7.0 8

phpMyAdmin version: 4.6.4

Client configuration

Browser: Firefox 50

Operating system: Windows 10

[acsfer]

I'm using Cloudflare, so this line is necessary:

$cfg['CSPAllow'] = 'ajax.cloudflare.com';