NTP server change causes switch disconnection issue
After changing the NTP server in the controller, all of the network SG2008 switches are now displaying DISCONNECTED in the Devices list. In the site's topology map they are also showing as being not connected. This can't be true as all network clients are working OK.
In my network there are 2 core switches with 2 switches downstream from one of the core switches. Oddly, the EAPs connected to the downstream switches are still showing as CONNECTED and everything is working as expected.
I'm not sure how to fix this issue without downing the network completely and rebooting everything. Suggestions ??
The switches are using the latest firmware (4.20.17 Build 20260121 Rel.53429). Removing or changing back to the old NTP server did not fix the problem. Rebooting the controller also did not solve the problem. The odd thing is that all the downstream access points were shown as connected. Traffic through the switches was normal and all clients in the Clients window were also shown as connected. A screenshot of the Devices window is shown below.
I did get things working again this morning by power cycling the two core switches. After that, the downstream switches did come back online after a short period. Later, I again changed the NTP server and everything occurred all over again. Like before, doing a power down/power up on the two core switches fixed everything. I have just configured a Synology NAS to be the local time server and after configuring the controller to use the local NTP server, the issue did not happen.