Working on a project where I'm needing to make FHIR calls from my HealthConnect Interop production to Epic.

My issue is I'm not able to construct a valid JWT for the OAuth token retrieval that Epic will accept. I have the below code where I'm able to create a valid header and payload that I'm base64URL encoding and then trying to sign with my .pem private key file. However, Epic is not liking the signature portion of my JWT.