Pre-trained model does not train

Is anyone know the reason why pre-trained model starts with good accuracy but after just jumping around this value and does not train.
On the image that I attached, I tried AlexNet with different numbers of batch, epochs, and optimizers.
I also tried other (VGG, ResNet) but results were similar.

The dataset that I use: Scratches on concrete surface (around 2000 images)

using a pretrained model often means your need a different lr. Have you changed it?

Nope, I always use lr=0.001, but I also use scheduler