The issue is observed after upgrading the switches from version 16.12.4 to 17.6.4. The problem revolves around the AAA server status being down intermittently, affecting user and device authentication. The software version 17.6.4 is the one being discussed in the context of this problem.
The documents discuss an issue in Cisco DNA Center's SDA Fabric Edge where the AAA server intermittently shows a down status after upgrading to software version 17.6.4. This impacts user and device authentication despite the radius status being up.