如果白名单IP不存在，PHP检查cookie（获取T_ELSEIF解析错误）

I'm not a PHP developer at all, this is a script provided by a theme to restrict access to whitelisted IP addresses. I'm hoping to amend it so that it if a whitelisted IP exists, it loads WordPress (as it does now), else if the IP does not exist in the array, it checks for a cookie. If the cookie exists (passedSecurityTT) show WordPress and lastly, if both do not exist - redirect to /login.php.

    <?php
    $whitelist = array('111.222.333.444', '111.222.333.445');
    if (in_array($_SERVER['REMOTE_ADDR'], $whitelist)) {

    define('WP_USE_THEMES', true);

    /** Loads the WordPress Environment and Template */
    require('./wp-blog-header.php');
    } else {
        //Action for all other IP Addresses
        echo 'You are not authorized here.'; 
        echo "<br />IP Address: ".$_SERVER['REMOTE_ADDR'];
        exit;
    }

elseif (!isset($_COOKIE['passedSecurityTT'])) {

    define('WP_USE_THEMES', true);

    /** Loads the WordPress Environment and Template */
    require('./wp-blog-header.php');
    } else {
        //Action for all other IP Addresses
        echo 'You are not authorized here.'; 
        echo "<br />IP Address: ".$_SERVER['REMOTE_ADDR'];
        exit;
    }


else {
header('Location: /login.php');
}

But I'm getting an error on Line 16: Parse error: syntax error, unexpected T_ELSEIF in /home/public_html/index.php on line 16

Can anyone help? Also thinking I should wrap this in a function somehow, as it's repeated...

define('WP_USE_THEMES', true);

    /** Loads the WordPress Environment and Template */
    require('./wp-blog-header.php');
    } else {
        //Action for all other IP Addresses
        echo 'You are not authorized here.'; 
        echo "<br />IP Address: ".$_SERVER['REMOTE_ADDR'];
        exit;
    }

<?php
$whitelist = array('111.222.333.444', '111.222.333.445');
// check if remote address is in whitelist OR if cookie exists(this is not the best security practice! @FIXME
if (in_array($_SERVER['REMOTE_ADDR'], $whitelist) || isset($_COOKIE['passedSecurityTT'])) ) {

    define('WP_USE_THEMES', true);

    /** Loads the WordPress Environment and Template */
    require('./wp-blog-header.php');
} else {
    header('Location: /login.php');
}

You can't have an elseif after an else:

<?php
$whitelist = array('111.222.333.444', '111.222.333.445');
if (in_array($_SERVER['REMOTE_ADDR'], $whitelist)) {

    define('WP_USE_THEMES', true);

     /** Loads the WordPress Environment and Template */
    require('./wp-blog-header.php');
} else {
    //Action for all other IP Addresses
    echo 'You are not authorized here.'; 
    echo "<br />IP Address: ".$_SERVER['REMOTE_ADDR'];   
    header('Location: /login.php');
    exit;
}