@Smok The Load Balancing feature will be not active when you enable link backup, because only one WAN online all the time.

@JackyBek It seems like here is the IP conflict in your network. Suggest you change the ER5120 LAN IP to another subnet to test, for example 192.168.10.1/24.

@rickestrick May I know the version of your controller? Can the tunnel establish when you set the L2TP/OpenVPN? All settings are the same as the standalone mode, but can not work on the controller?

@Shoresy I'm afraid it doesn't support, if you search " LACP" in the User Guide, it will show nothing. And I also can't find " 802.3ad " on the SPEC.

@Borjebus You can just connect a PC to router with an Ethernet cable like this: Router----PC. Then set a static IP address like 192.168.0.10 on this PC. And try to ping router's default IP address...

@Lutz_GER This error message is because your ISP is not returning echo request packages so that the link is broken. Suggest that you check with your ISP first to see if there is any network...