I see you both use X-Payments Enterprise/Downloadable licenses.
Most likely your hosting disabled SSLv3 due to POODLE - see https://www.digitalocean.com/community/tutorials/how-to-protect-your-server-against-the-poodle-sslv3-vulnerability
Your version of X-Cart connector for X-Payments may require SSLv3 and that's why it stopped working all of sudden.
We are preparing a newsletter about what to do. Please stay tuned and I will post an update shortly today.