OAuth via API Connector 400 Error

Hello, I am using an API Connector in my google sheets to pull in account data with all characters and level information. Just got started, someone suggested using this API Connector extension and make a customer OAuth connection, which i did input the
Autorize and Token URLs:
**oauthbattlenet/authorize & **oauthbattlenet/token
Based on Blizzard’s API Documentation, used the Client Secret & Client ID as prompted, but still get a 400 Invalid grant type or callback URL is not valid Error.

I have tried not using any Callback URL as the opiton is availabed in the Client Setup when creating. I have also tried using a Callback URL of developbattlenet

Anyone have any thoughts or maybe a better way, i was going to possibly look into just doing a custom script for this, but was hoping using a quick API Connector and just pulling all the account data to a sheet would be the quicker route.