The GET /crm/v3/imports/ endpoint needs to functional through " OAuth ". It only supports " API key " now. Unlike many other HubSpot endpoints in the imports, API, this one in particular is documented to not work through 0Auth.
Hey, HubSpot Developers! There are plenty of questions about the upcoming sunset and how to migrate your apps using API keys to use Private Apps.
Luckily, our amazing team put together this guide, Migrate an API key integration to a private a read more