Hello @+NYCWMG Adopsbot
Thanks for reaching out to Microsoft Q&A platform! To connect to your resource, you need to use API key and Endpoint URL not your Azure Subscription.
Please check on below screenshot:
- Go to your resource and click "Keys and Endpoint"

2) Then you can see the key you need and the endpoint url as below

Both keys work, just choose one of them. I hope this helps!
If you need more infomation about how to set up with SDK, please check on this guidance - https://learn.microsoft.com/en-us/azure/applied-ai-services/form-recognizer/quickstarts/get-started-v3-sdk-rest-api?pivots=programming-language-csharp
Regards,
Yutong
-Please kindly accept the answer if you feel helpful to support the community, thanks a lot.