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=8addc78709&notice_str=2315858402&hash=1623290bac271db5e59203c22adb22b2&redirect_to=https%3A%2F%2Fu.limo%2Ftag%2F%25E7%2594%25B5%25E5%25AD%2590%25E7%259B%25B8%25E5%2586%258C%25E7%2585%25A7%25E7%2589%2587%25E7%259B%25B8%25E6%25A1%2586%2F' caused an error:

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