Pull requests diff endpoint returns "This endpoint does not support token-based authentication"

https://api.bitbucket.org/2.0/repositories/

{username}/{repo_slug}/pullrequests/{pull_request_id} works as expected

https://api.bitbucket.org/2.0/repositories/{username}

/

{repo_slug}

/pullrequests/

{pull_request_id}

/diff does not work: Returns "This endpoint does not support token-based authentication"