How to add new class to existing dataset?

I am trying to add 1 new class to existing 20 classes of VOC dataset. I am new to tensorflow and following this tutorial: TensorFlow Object Detection API tutorial — TensorFlow Object Detection API tutorial documentation. Unfortunately total loss never was less than around 10 and after 30000 steps it started increasing. I also tried to train with 20 original classes but result was the same.

log is here:

My setup:

  • AMD Radeon RX570 GPU
  • Windows 10
  • DirectML
  • Tensorflow 1.15
  • TensorFlow Model v.1.13.0

Any help will be highly appreciated.