Kafka Consumer does not receive data

Question

I have worked out a Kafka concept which is built up in such a way that I have a series of machines which have electric airpressure dustextraction and machinenStatus data. I have set up my Kafka concept in such a way that I create a topic for each machine and each topic has 4 partitions. The partitions are then structured so that airPressureData is placed on partition 0, electricData on partition 1, dustExtractionData on partition 2 and MachineStatus Data on partition 3. I have now written 4 consumers which each subscribe to the individual partitions of the topics using consumer.Assing(). However, I get no data although the producer writes the correct data to the correct partitions. Here is another example consumer:

using System.IO.Compression;
using Confluent.Kafka;
using EnergyMeasurement.Models;
using Microsoft.Extensions.Hosting;
using Microsoft.Extensions.Logging;
 public class AirPressureConsumerService : BackgroundService
    {
        private readonly ILogger<AirPressureConsumerService> logger;
        private readonly List<string> topics;
        private readonly string groupId = "coldPath";
        private readonly string bootstrapServers = "localhost:9092";

        public AirPressureConsumerService(ILogger<AirPressureConsumerService> logger)
        {
            this.logger = logger;
            this.topics = new List<string> { "thingId1", "thingId2" };
        }

      protected override async Task ExecuteAsync(CancellationToken stoppingToken)
    {
        var config = new ConsumerConfig
        {
            BootstrapServers = this.bootstrapServers,
            GroupId = this.groupId,
            AutoOffsetReset = AutoOffsetReset.Earliest
        };

        using var consumer = new ConsumerBuilder<Ignore, byte[]>(config).Build();

        foreach (var topic in this.topics)
        {
            var topicPartition = new TopicPartition(topic, 0);
            consumer.Assign(topicPartition);

            while (!stoppingToken.IsCancellationRequested)
            {
                var consumeResult = consumer.Consume(stoppingToken);

                var compressedDto = CompressedDTO.Parser.ParseFrom(consumeResult.Message.Value);
                var contentBytes = Decompress(compressedDto.CompressedData.ToByteArray());

                var airPressureDTO = AirPressureDTO.Parser.ParseFrom(contentBytes);

                Console.WriteLine($"Received message at {consumeResult.TopicPartitionOffset}: {airPressureDTO}");
                await Task.Delay(1000, stoppingToken);
            }
        }

        consumer.Close();
    }

        private byte[] Decompress(byte[] data)
        {
            using var compressedStream = new MemoryStream(data);
            using var decompressStream = new GZipStream(compressedStream, CompressionMode.Decompress);
            using var resultStream = new MemoryStream();
            decompressStream.CopyTo(resultStream);
            return resultStream.ToArray();
        }
    }

I have checked that the producers write to the correct topics and partitions. I also tried to sign on the whole topic, then I get data. I don't understand why I don't get the data this way.

using Microsoft.Extensions.DependencyInjection;
using Microsoft.Extensions.Hosting;

public class Program
{
    public static void Main(string[] args)
    {
        CreateHostBuilder(args).Build().Run();
    }

    public static IHostBuilder CreateHostBuilder(string[] args) =>
        Host.CreateDefaultBuilder(args)
            .ConfigureServices((hostContext, services) =>
            {
                services.AddHostedService<ElectricConsumerService>();
                services.AddHostedService<AirPressureConsumerService>();
                services.AddHostedService<MachineStatusConsumerService>();
                services.AddHostedService<DustExtractionConsumerService>();
                services.AddHostedService<TestConsumer>();
            });
}