Error: 404 Not Found

Sorry, the requested URL 'http://u.limo/wp-admin/admin-ajax.php?channel_id=social_wechat&action=xh_social_channel&tab=login_redirect_to_authorization_uri&xh_social_channel=68232355da&notice_str=5219611818&hash=8bd50afae251c06987383c9e6ca6ff5f&redirect_to=https%3A%2F%2Fu.limo%2Fpr%2Fpremiere-cc-2018%2F' caused an error:

Not found: '/wp-admin/admin-ajax.php'