I get an ObjectDisposedException when reading a stream in the background service

Question

I want to process a Request.Body in a background-service in ASP.Net Core, so I first add it to a ConcurrentQueue.

public class BackgroundJobs
{
    public ConcurrentQueue<Stream> Queue { get; set; } = new ConcurrentQueue<Stream>();
}

The concurrentQueue is instantiated with AddSingleton in Startup.cs

[ApiController]
public class NotificationsController : ControllerBase
{
    private readonly BackgroundJobs backgroundJobs;

    public NotificationsController( BackgroundJobs backgroundJobs)
    {
        this.backgroundJobs = backgroundJobs;
    }

    //...........
    [HttpPost]
    public ActionResult<string> Post([FromQuery] string validationToken = null)
    {
        if (!string.IsNullOrEmpty(validationToken))
        {
            return Ok(validationToken);
        }
        else
        {
            backgroundJobs.Queue.Enqueue(Request.Body);

            return Accepted();
        }
    }
}

BackgroundServices.cs was instantiated in Startup.cs with AddHostedService. When the Request.Body is in the queue I want to process it further.

public class BackgroundServices : BackgroundService, IHostedService
{
    private readonly BackgroundJobs backgroundJobs;

    private IServiceScopeFactory iServiceScopeFactory;

    public BackgroundServices(BackgroundJobs backgroundJobs, IServiceScopeFactory iServiceScopeFactory)
    {
        this.backgroundJobs = backgroundJobs;
        this.iServiceScopeFactory = iServiceScopeFactory;
    }

    protected override async Task ExecuteAsync(CancellationToken cancellationToken)
    {
        Stream stream;

        while (!cancellationToken.IsCancellationRequested)
        {
            if (this.backgroundJobs.Queue.TryDequeue(out stream))
            {
                StreamReader streamReader = new StreamReader(stream);
                string content = await streamReader.ReadToEndAsync();
                var list = JsonConvert.DeserializeObject<Notifications>(content)
                //......

But get on string content = await streamReader.ReadToEndAsync() the following error message: System.ObjectDisposedException in System.Private.CoreLib.dll