System.Net.HttpRequestException: "An error occured while sending the request", Inner Exception: "The response ended prematurely"

All of these are on .NET Core 3.1

I've created an MVC project with individual user accounts stored in-app for authentication and I will be using it as an api. The API looks like this:

[Route("api/[controller]")]
[ApiController]
public class ValuesController : ControllerBase
{
    // GET: api/Values
    [HttpGet]
    public IEnumerable<string> Get()
    {
        return new string[] { "value1", "value2" };
    }

    // GET: api/Values/5
    [HttpGet("{id}", Name = "Get")]
    public string Get(int id)
    {
        return "value";
    }
}

and a Blazor Server-side project to fetch data from that API.

@page "/fetchvalues"
@using System.Net.Http

<h3>FetchValues</h3>
<button @onclick="GetData">Get values</button>

@if (output != null)
{
    <table>
        @foreach (var item in output)
        {
            <tr>
                <td>@item</td>
            </tr>
        }
    </table>
}

@code {

    private HttpClient client = new HttpClient();

    private List<string> output = null;

    private async void GetData()
    {
        output = await client.GetJsonAsync<List<string>>("http://localhost:5001/api/values");
    }
}

and the output looks like this: