IPv4 to IPv6

It might be that your ISP is using IPv6 and tunneling IPv4 via CG-NAT and DS-Lite.

While IPv6 is generally a Good Thing to have (as the Xbox One primarily uses IPv6, and even if you only have IPv4, it will use IPv6 tunneled through IPv4), you might want to check with your ISP if they offer you a "Dual Stack" connection with IPv6 and a
real public IPv4 in parallel.

There really isn't much you can do on the console itself, as it does check automatically what IP protocol your ISP provides, and if it's IPv6, then the console will use IPv6. If it's a Dual Stack, where you have IPv4 natively (not tunneled through IPv6)
and IPv6, then the console will use both, and if it's an IPv4 connection, it'll tunnel IPv6 through IPv4 through Teredo.

Do you know if you ISP supports IPv6? Your router could be tunneling your IPv4 connection to an IPv6 which basically means it is sending IPv6 packets through an IPv4 connection to communicate with IPv6 servers. I found out myself the xbox doesn't
like this at all. My ISP doesnt support IPv6. When I would look at my connection on my xbox it would say IPv4 and IPv6. So O went into my router settings and sure enough my router was set to tunnel IPv4 to IPv6. I went through set to IPv4 only and it solved
my problem. This causes a teredo error in your xbox.

I'm not sure. How can I check if my router is tunneling it through Ipv4?

Do you know if you ISP supports IPv6? Your router could be tunneling your IPv4 connection to an IPv6 which basically means it is sending IPv6 packets through an IPv4 connection to communicate with IPv6 servers. I found out myself the xbox doesn't like
this at all. My ISP doesnt support IPv6. When I would look at my connection on my xbox it would say IPv4 and IPv6. So O went into my router settings and sure enough my router was set to tunnel IPv4 to IPv6. I went through set to IPv4 only and it solved my
problem. This causes a teredo error in your xbox.

The Problem could be: Do you have IPv6 AND IPv4 on your router? If yes try to disable IPv6 and restart your router so you only have IPv4. XBOX has some Problems with IPv6 at the moment

Does xbox1 stil run on ipv4 or do you have to be on ipv6

It xbox one supports ipv6 nativity. It can support ipv4. It is really up to carrier if you are able to get an ipv6 connection.