If you see the following error message...

Parse error: syntax error, unexpected T_FUNCTION in ...themes/vysualize/functions.php on line 5

...This means you're hosting has strict server permission active. To address this, open functions.php and locate the following on lines 2-20...

//////////////////////////////////////////
//ADJUST WP_oEMBED_GET FOR HTML VALIDATION
//////////////////////////////////////////
add_filter( 'oembed_dataparse',zfunction( $return, $data, $url ) {
    // Target only Vimeo:
    if( is_object( $data ) &&  property_exists( $data, 'provider_name' ) &&  'Vimeo' === $data->provider_name || 'YouTube' === $data->provider_name ) {
        // Remove the unwanted attributes:
        $return = str_ireplace(
            array(
                'frameborder="0"',
                'webkitallowfullscreen',
                'mozallowfullscreen'
            ),
            '',
            $return
        );
    }
    return $return;
}, 10, 3 );

...replace it with this...

//////////////////////////////////////////
//ADJUST WP_oEMBED_GET FOR HTML VALIDATION
//////////////////////////////////////////
function embedfunc( $return, $data, $url ) {
    // Target only Vimeo:
    if( is_object( $data ) &&  property_exists( $data, 'provider_name' ) &&  'Vimeo' === $data->provider_name || 'YouTube' === $data->provider_name ) {
        // Remove the unwanted attributes:
        $return = str_ireplace(
            array(
                'frameborder="0"',
                'webkitallowfullscreen',
                'mozallowfullscreen'
            ),
            '',
            $return
        );
    }
    return $return;
}
add_filter( 'oembed_dataparse', 'embedfunc', 10, 3 );