OAuth2 Application generates Access Token but gives 401 when trying to consume Workfront Planning APIs

I successfully exchange the JWT Token for an Access Token when using an OAuth2 Application in Adobe Workfront => Setup => System => OAuth2 Applications.

I try to use the generated Access Token to consume Workfront Planning API.

For example: https://{customer-domain}/maestro/api/v1/workspaces

I end up getting 401 Unauthorized.