Netbird inside LXC container not updating

I’m running several services inside LXC containers on a Proxmox host. These LXC’s have been updated from Ubuntu 24.04 LTS to Ubuntu 26.04 LTS. I think since this upgrade, Netbird will not update itself when running apt update & apt upgrade. I think the Netbird repository is missing in the container. I have tried to add it to the repository list, but then I get an error saying that the repository is missing a public key and can not be trusted.

Does anybody know how I can update the containers?

Edit: so I asked too soon. What I did was just run an apt remove netbird and then reinstall it with the curl command in the documentation. This reinstalls the repository. I will leave this topic here if somebody else runs into this problem.