the metric is low in custom dataset

[wu33learn]

i train 20 epoch like the cat example ,lr= 0.0001
the cat data contains 144 images, my data has 1260(train), 180(test), the data is about industrial metal surface.
https://github.com/open-mmlab/mmdetection/blob/main/configs/grounding_dino/README.md#4-model-training-and-visualization

epoch 16 best

epoch 20

is mm grounding dino model not suitable? how can i train mm grounding dino model for this domain?