@KimcheeGUN After your suggestion, I tried to upgrade the TL-SG3452P v3.0 from 3.0.1 to 3.0.2 , using the upgrade button in the Omada controller software again. After upgrading the device went...

Over the last weeks, there have been several mentions of issues with the upgrade to switches using the Omada controller software. See: https://community.tp-link.com/en/business/forum/topic/581064 I...

@Hank21 This happens to me too. I administer two separate TP-Link network installations and all my reboot schedules on one network fail since 17-1-2022 and since last week also on the second network....

You could change the WiFi password and communicate it to the teachers. But probably it is time to look for a better authentication mechanism bbased on logging on with a more authoritative identity...