We're unable to connect to the Marketplace, Maybe check your Internet connection

I'm having serious issues on Xbox logging in to the marketplace with my profile in the Minecraft Beta

Error: "We're unable to connect to the Marketplace, Maybe check your Internet connection." Internet is fine. NAT is open.

My son can login to the marketplace fine on our shared Xbox One X (the same console)

When I try on my other Xbox, which is a Series X. I get the same issue.
Internet and NAT are also fine on that console.

I can still load my saved worlds and download them from the cloud save.

I've tried uninstalling Minecraft and my save on the Series X and then reinstalling but still no luck.

I'm at a loss as to what could be causing this.

I can open the marketplace on bedrock on Windows 10 PC without an issue, so it's just happening on Xbox!

I tried asking about this in various Minecraft community support forums and discord and I contacted Minecraft official support who said they can't do any remote troubleshooting?
I'm a third level Windows engineer I'm happy to help facilitate any required remote access that may be needed to help me fix this issue. 

I've been trying to find a solution for this issue for over a week now and I'm getting a bit frustrated.