NSW100-28p no longer connected to nebula, but traffic works

Simultux · March 2023

Hi, I have a strange situation with a NSW100-28p after a power outage. The ALM led blinks red, Connection to nebula seems down as device shows up as offline, however traffic through the switch and security gateway to the internet works just fine, including to devices connected behind the switch (there is a second switch on one of the SFP uplinks and that one connects to nebula quite fine).
Topology: WAN→NSG50→NSW100-28P→XGS1930-52
The NSG50 and the XGS1930 show up on nebula as online, however the NSW100-28p in between them does not any more, worked fine before the power outage. Powercycling the switch or rebooting the NSG did not help.
How can I resolve this?
Firmware-version is V3.00(ABBT.2) | 11/19/2019 (Stable)