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=93a3146821&notice_str=3143192510&hash=8330990cf3515a296fd4e9fb9cf0dd06&redirect_to=https%3A%2F%2Fu.limo%2F14050%2F' caused an error:

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