Error message does not contain details

I am using the Go library and it seems it is using gRPC internally.
cloud.google.com/go/vertexai/genai

I got the following error when using a fine-tuned model from Vertex.
The request contains what? What is the invalid argument?

rpc error: code = Invalid Argument desc = Request contains an invalid argument.

Without knowing what caused the issue, it is painfully difficult to debug.