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=4522642138&hash=1211ac984ea046ce4f206411f63e08f6&redirect_to=https%3A%2F%2Fu.limo%2Ftag%2F%25E7%2589%2587%25E5%25A4%25B4%25E5%25B0%2581%25E9%259D%25A2%2F' caused an error:

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