Circle is a device to protect young persons usage of the internet.
detailed how it works page here:
https://support.meetcircle.com/hc/en-us/articles/115001381932-How-Does-C...
Here is the circle suppt router list:
https://support.meetcircle.com/hc/en-us/articles/115001381571
Note that I setup a Circle device and it is working with myopenrouter on a Netlink EX6200
I had to uncheck ARP Spoofing Protection under Security,Firewall.