Passing async method to Func Task Bool

I have written a client that saves files to Azure. There is an async method as follows that that I want to pass down to the repository where I want to be able to invoke the SaveFile() method inside a transaction.

My Azure file client as follows:

public async Task<bool> SaveFile(string customerId, string fileName, byte[] data)
{
    try
    {
        var directory = await RetrieveDirectory(customerId);
        var file = directory.GetFileReference(fileName);
        await file.UploadFromByteArrayAsync(data, 0, data.Length);
        return true;
    }
    catch (Exception ex)
    {
        _logger.LogError("Unable to save file on Azure storage for customer {0} and filename {1}. Exception {2}", customerId, fileName, ex.ToString());
    }
    return false;
}

From the CommandHandler I do:

if (await _translationAttachmentService.CreateTranslationAttachment(
    command.CustomerId, attachment,
    () => client.SaveFile(command.CustomerId.ToString(), command.FileType, command.Data)))
{
    return new CommandResult<TranslationAttachment>(true, attachment);
}

The Transaction is reached by sending the callback from the CommandHandler via the Service, only calling the Repository which is below:

   public async Task CreateTranslationAttachmentByTranslationIdAsync (TranslationAttachment attachment, Func<Task<bool>> callback)
    {
        using (var transaction = await _context.Database.BeginTransactionAsync())
        {
            await _context.Set<TranslationAttachment>().AddAsync(attachment);

            var result = await callback();

            if (result)
            {
                transaction.Commit();
            }
            else
            {
                transaction.Rollback();
                throw new Exception("Unable to save file.");
            }
        }
    }

When reaching the Repository method the thread jumps down straight after adding the Attachment Entity to transaction.Rollback(). I never reach the breakpoint in the SaveFile() method so I suspect I am misusing async in some way.

Many thanks in advance for any help!