@PiLYo1 I think that that the VPN is a good choice for you. If you use "Connected Via LAN", you will see that Router 1 and Router 2 are connecting to the same switch. Due to two different NAT and...

@Nicap The Username and Password is on the "Setting--Site--Device Account", you can try to use this username and password to adopt the ER605. Also you can try to power off ER605 and your controller,...

@drgonzoo Try to use the Username and Password on the "Setting-Site-Device Account" to manually adopt the ER7206. Did the devices in the network all belong to subnet 192.168.0.x? Or maybe you can try...

@JK_ The issue is similar to this topic. https://community.tp-link.com/en/business/forum/topic/262944

@drgonzoo You can try to reboot both the OC300 and ER7206, after power off these two devices, wait for 2 minutes and power back on. Then try to login the Controller to adopt the ER7206. If still...

@franco65 Simply, if you want to make the EAP using the Public IP address from your internet service provider, you can disable the DHCP function on the Edgerouter-4, which is similar working in the...