Model Predicts Always the same Class

Hello, I have problem with my Model.
My Model Predicts always the Same class in Validation and Test. The Prediction in Training works fine, or better, than in Validation and test. I tried to use the same data in Training, Validation and Test but every time comes the same result. I tried to optimize the Learn rate without success. My Data is also good, Equalized over all classes. I’m using a MC3 model.

Can someone help me with this problem, or giving me a hint where my problem might be?