Messenger Kids not working.

For some reason, my children are unable to use Messenger Kids when attempting to video call or message a friend. I've attempted every troubleshooting step I can think of, including direct routing and access control. Nothing seems to work unless I completely disconnect my Deeper Connect Mini and connect my router directly to my ISP modem. I'm using a Ubiquiti UniFi Max gateway. However, my UniFi gateway isn't showing my network devices in access control; only the gateway itself is visible there.