Ipv4 to ipv6?
Ipv4 to ipv6?
Certain ISPs offer dual-stack IP addresses, providing both IPv4 and IPv6. Those running low on IPv4 addresses are adopting carrier-grade NAT solutions. As noted by @Windows7ge, if your network uses IPv6, it shouldn't impact your internet access since ISPs assign routable addresses, and most modern routers support both protocols. Who is your ISP?
Your router serves as a bridge between networks. When a website uses only IPv4, the data packet arrives at your router, which adds an IPv6 header for communication within your local network. If you encounter issues accessing these services, it may relate to the protocol version rather than your device. Additionally, every web request to the internet queries your ISP's DNS server, meaning that even with IPv6, you're ultimately interacting with IPv4 servers.
In fact, when there’s nothing to translate between IPv4 and IPv6 from an IPv6-only network, it means you can’t reach IPv4-only sites. I’d guess his ISP hasn’t fully switched to IPv6 yet and still uses IPv4—likely with CGNAT—but the IPv4 is blocked on the adapter. Can you check if other sites work on your phone or another device?
I'm assuming the router had both IPv4 and IPv6 assigned to the WAN port, while another person turned off IPv4 on their device.