@xcoaster1 Maybe you can try to downgrade R600VPN to check if the issue is related to the latest firmware.

@Ahbaid T1600G-28TS V2 should only has one firmware. Just the factory firmware. So haven't the updated firmware version. Did you have any problem that need to solve by a new firmware?

@Apichat The configuration of R600VPN has not problem. Do you make sure you have shown all settings for SEL3620? It seems that R600VPN did not receive the reply from SEL3620. Maybe related to the...

@MHenriques It seems that you will get the warning every 20 minutes or 25 minutes. As I knew, SNMP may cause the high CPU usage. You can check if your SNMP software also get some information from...

@Irongripper The switch uses the IP address of 192.168.0.1 by default. I suggest to remove the switch from the network. Then connect a PC to the switch. Set static IP adderss for your PC like...

@GA79DUD You need 2 LAN port and 1 PoE port, you can use TL-SG1005P. https://www.tp-link.com/en/business-networking/unmanaged-switch/tl-sg1005p/