Okta Api - Get Emails using DPoP token

I am using DPoP token flow to get the access token and call Okta Apis. All seem to be working fine (getting/creating users, getting/creating groups etc.). I am in need to call the
$“{oktaDomain}/idp/myaccount/emails" - to retrieve e-mails. No matter what scopes I add to my service app, I keep getting a 403 with the following error in response body:
{“errorCode”:“E0000005”,“errorSummary”:“Invalid session”,“errorLink”:“E0000005”,“errorId”:"oaeiX_nO3eUT
-YJxWYYX9-Yw”,“errorCauses”:}
Would someone please help and let me know what am I doing wrong?
Thank you!

The MyAccount APIs need to receive user specific tokens, but I get the sense that you are trying to use an access token issued to a API Service app against this endpoint.

Check this guide out about how to get tokens for a user instead of for a service app: Implement OAuth for Okta | Okta Developer