Finesse REST API C#

[Paul Hansen]

Using Postman, I am getting:

Get http://192.168.8.58/finesse/api/User/tagent

basic auth:

<ApiErrors>
    <ApiError>
        <ErrorType>Invalid Authorization User Specified</ErrorType>
        <ErrorData>tagent</ErrorData>
        <ErrorMessage>The user specified in the authentication credentials and the uri don&apos;t match</ErrorMessage>
    </ApiError>
</ApiErrors>

How can I get that users information?