You are validating client association capabilities to an 802.1X/EAP secure SSID. The RADIUS server's IP address is 10.100.50.25, and the default RADIUS authentication port is being used. None of the clients can associate with the SSID. After verifying that both the server and the RADIUS service are operational, you find that the authenticator (such as the AP or controller) is not communicating properly with the RADIUS server. What is your next troubleshooting step?