Hi! I’m having the same issue as @APear .
I wanted to migrate from API Key To Private app for my solution , I managed to use the private app token for a simple getcontacts call using HttpClient (Bearer autorization and private app token) but I could NOT make it work for HubSpotApi calls that requires ApiKey (i tried with OAUTH var api = new HubSpotApi(“clientID”, “clientSecret”, “HubSpotAppID”); It says is expecting an API key instead)
I would be grateful for any advice.