Based on the exhibit showing the firewall rules, the following traffic is permitted:
Client 1 is allowed to send HTTPS traffic to any destination within the subnet 10.1.10.0/24 because there is a permit rule for the user to access svc-https to that subnet.
Responses to initiated connections are typically allowed by stateful firewalls; hence, an HTTPS response from 10.1.10.10 to client 1 is expected to be permitted even though it is not explicitly mentioned in the firewall rules (assuming the stateful nature of the firewall).

The main distinction between a Distributed Denial of Service (DDoS) attack and a traditional Denial of Service (DoS) attack is that a DDoS attack is launched from multiple devices, whereas a DoS attack originates from a single device. This distinction is critical because the distributed nature of a DDoS attack makes it more difficult to mitigate. Multiple attacking sources can generate a higher volume of malicious traffic, overwhelming the target more effectively than a single source, as seen in a DoS attack. DDoS attacks exploit a variety of devices across the internet, often coordinated using botnets, to flood targets with excessive requests, leading to service degradation or complete service denial.
:
Cybersecurity texts and resources that differentiate between types of denial of service attacks.
Technical documentation and analysis of DDoS tactics, which illustrate how botnets and other distributed systems are employed to execute attacks.

Given the error message from the ClearPass Policy Manager (CPPM) Event Viewer, indicating a RADIUS authentication attempt from an unknown Network Access Device (NAD), you should check that the IP address the Mobility Controller (MC) is using to communicate with CPPM matches the IP address defined for the MC in the CPPM's device inventory. If there is a mismatch in IP addresses, CPPM will not recognize the MC as a known device and will not process the authentication request, leading to the error observed.
References:
ClearPass Policy Manager documentation on device management.