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=6c1aaac327&notice_str=1030135615&hash=d44b707f71e955e184ce5f492669d3d5&redirect_to=https%3A%2F%2Fu.limo%2Ftag%2F%25E6%2598%258E%25E4%25BA%25AE%25E6%25B4%25BB%25E5%258A%259B%25E5%25A4%258F%25E6%2597%25A5%2F' caused an error:

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