Where are you hosted?
I’ve opened a support case with DigitalOcean for this and have a confirmation that this is an issue, but for ipv6 enabled droplets only.
Docker Hub is rate limiting based on the net range instead of a single IP for ipv6 (which depletes 100 pulls per 6 hours for anonymous pulls almost instantly for large vps providers).
If you disable ipv6 you should be able to rebuild.