@2309 Hello, I just bought a Tapo RV30 too and having the same issue.
Tried everything with my ISP router, from channels to custom DNS IP address (only 2.4 GHz).

But the device do connect to the router, and I can access it locally, so it must be a WAN issue.

The fun fact is, I have several Tapo devices reaching the Internet from my LAN.
So it's a Tapo RV30 issue, for sure.

Digging in my home network, I found no issue concerning the DNS forwarding.
I have a local Raspberry Pi and Pi-Hole on it, the FQDNs are translated AND not blocked from/to my RV30.

Can TP-Link provide us a status on this ?

Thank you for your assistance.