How to convert .onnx model from qpic.pth

[bj-noh]

I am facing some issue; onnx conversion of this model.
I tried

torch.onnx.export(pth_model, dummy_input, "onnx_model.onnx", opset_version 11)
dummy_input shape is [1, 3, 720, 1280] # same with this model.

However, the result is
[array([[[nan, nan, nan],
[nan, nan, nan]]], dtype=float32), array([[[nan, nan],
[nan, nan]]], dtype=float32), array([[[nan, nan, nan, nan],
[nan, nan, nan, nan]]], dtype=float32), array([[[nan, nan, nan, nan],
[nan, nan, nan, nan]]], dtype=float32)]

It's nan party!

please commet how to fix it.