I’m trying to remove attachments from a draft email when forwarding it using the Microsoft Graph API in a C# application. However, I’m encountering a “tooManyRetries” error when trying to delete the attachments.

Here is the relevant code:

private static async Task<Message> GetDraftMessageAsync(GraphServiceClient client, EmailCreateServiceModel model,
                                                       ComposeMode mode, CancellationToken cancellationToken)
{
    //other modes

    var message = await client.Users[model.OriginalEmailAddress]
        .Messages[model.MessageId]
        .CreateForward()
        .Request()
        .Header("Prefer", "IdType="ImmutableId"")
        .PostAsync(cancellationToken)
        .ConfigureAwait(false);

    // Question 1: can I somehow get the draft message with attachments without this second call?
    var messageWithAttachments = await client.Users[model.OriginalEmailAddress]
        .Messages[message.Id]
        .Request()
        .Expand(m => m.Attachments)
        .GetAsync(cancellationToken)
        .ConfigureAwait(false);

    return messageWithAttachments;
}

public static async Task<Message> SendEmailAsync(EmailCreateServiceModel model, ComposeMode mode, List<string> keepingAttachments,
                                                  CancellationToken cancellationToken)
{
    var client = await AuthService.GetGraphClientAsync();
    var draftMessage = await GetDraftMessageAsync(client, model, mode, cancellationToken)
                .ConfigureAwait(false);

    if (mode is ComposeMode.Forward && draftMessage.Attachments != null)
    {
        var attachmentsToRemove = draftMessage.Attachments
            .Where(attachment => !keepingAttachments.Contains(attachment.Name))
            .ToList();

        foreach (var attachment in attachmentsToRemove)
        {
            // Question 2: This code hangs for a long time and then throws the exception
            await client.Users[model.OriginalEmailAddress]
                .Messages[draftMessage.Id]
                .Attachments[attachment.Id]
                .Request()
                .DeleteAsync(cancellationToken)
                .ConfigureAwait(false);
        }
    }

    draftMessage.From = string.IsNullOrEmpty(model.From)
        ? null
        : new() { EmailAddress = new() { Address = model.From } };
    draftMessage.ToRecipients = GetRecipients(model.To);
    draftMessage.CcRecipients = GetRecipients(model.Cc);
    draftMessage.BccRecipients = GetRecipients(model.Bcc);
    draftMessage.Subject = model.Subject;
    draftMessage.Body = new ItemBody() { Content = model.Body, ContentType = BodyType.Html, };

    draftMessage = await client.Users[model.OriginalEmailAddress]
            .Messages[draftMessage.Id]
            .Request()
            .UpdateAsync(draftMessage, cancellationToken)
            .ConfigureAwait(false);
}

Problem:

1. Can I somehow get the draft message with attachments without making
   a second call?
2. The code (from the part shown) hangs for a long time and then throws an
   exception when trying to delete attachments from the draft message.

Error Details:

Microsoft.Graph.ServiceException
  HResult=0x80131500
  Message=Code: tooManyRetries
  Message: More than 3 retries encountered while sending the request.

  Source=Microsoft.Graph.Core
  StackTrace:
   at Microsoft.Graph.HttpProvider.<SendRequestAsync>d__19.MoveNext()
   at System.Runtime.ExceptionServices.ExceptionDispatchInfo.Throw()
   ...
   at Microsoft.Graph.AttachmentRequest.<DeleteAsync>d__3.MoveNext() in AttachmentRequest.cs
   ...

Questions:

1. Is there a specific permission required to delete attachments from a draft message?
2. Is there an issue with how I’m fetching and modifying the draft message?
3. How can I handle the “tooManyRetries” error properly?
   Any help or guidance on resolving this issue would be greatly appreciated.