Didn’t work for me till I looked at the file at /wp-content/plugins/newsletter/profile/profile.php:
function hook_wp_loaded() {
global $wpdb;
$this->home_url = home_url(‘/’);
switch (Newsletter::instance()->action) {
case ‘profile_export’:
$user = $this->get_user_from_request(true);
header(‘Content-Type: application/json;chartse=UTF-8’);
echo $this->to_json($user);
die();
}
there’s a typo there: it should read: header(‘Content-Type: application/json;charset=UTF-8’);
At least, once I’d corrected it, the link worked