Using UmbracoMemberAuthorize in custom API controller: How to return only 401 code and not the error page?

I've this code:

            [UmbracoMemberAuthorize("", "Socio", "")]
    [ActionName("Content")]
    [HttpGet]
    public async Task<IActionResult> Content(Guid id)
    {
        var content = _contentService.GetById(id);

        var flag = await IsAuthorizedToSeeData(id);

        if (flag)
        {
            return Ok(ContentFor(id));
        }
        else
            return Unauthorized();

    }

I wish to return 401 and not go to the login/error page.