It’s intentional. They intend on getting it back up again later. But maybe as a seperate endpoint or something.
This is what Korakk said on Discord:
Sorry for the inconvenience friends! The auction endpoints have been re-enabled, however they no longer contain commodity data. I will be posting an update in the API forums tomorrow outlining the plan for that data. We appreciate your patience, I know breaking API changes on the fly are not ideal .