Hi
Please check below error

Notice: values in /var/www/html/wordpresstest/wp-content/plugins/rebel-slider/admin/cmb2-add-ons/cmb2-slide-effects/cmb2-slide-effect.php on line 15

Notice: Undefined variable: slider_nr in /var/www/html/wordpresstest/wp-content/plugins/rebel-slider/admin/cmb2-add-ons/cmb2-slide-effects/cmb2-slide-effect.php on line 16

Notice: wp_enqueue_script was called incorrectly. Scripts and styles should not be registered or enqueued until the wp_enqueue_scripts, admin_enqueue_scripts, or login_enqueue_scripts hooks. Please see Debugging in WordPress for more information. (This message was added in version 3.3.0.) in /var/www/html/wordpresstest/wp-includes/functions.php on line 4161

Notice: Use of undefined constant RS_PLUGIN_FILE – assumed ‘RS_PLUGIN_FILE’ in /var/www/html/wordpresstest/wp-content/plugins/rebel-slider/admin/plugin-welcome/welcome-init.php on line 43

Notice: Use of undefined constant RB_PLUGIN_FILE – assumed ‘RB_PLUGIN_FILE’ in /var/www/html/wordpresstest/wp-content/plugins/rebel-slider/admin/plugin-welcome/welcome-init.php on line 58

Notice: Use of undefined constant RS_PLUGIN_FILE – assumed ‘RS_PLUGIN_FILE’ in /var/www/html/wordpresstest/wp-content/plugins/rebel-slider/includes/class-rebel-slider.php on line 240

Thanks