Improve error message for when an LLM base model can't be loaded. (#3675

)

ludwig/schema/llms/base_model.py

@@ -59,9 +59,11 @@ def validate(model_name: str):
                 return model_name
             except OSError:
                 raise ConfigValidationError(
-                    f"Specified base model `{model_name}` is not a valid pretrained CausalLM listed on huggingface "
-                    "or a valid local directory containing the weights for a pretrained CausalLM from huggingface."
-                    "Please see: https://huggingface.co/models?pipeline_tag=text-generation&sort=downloads"
+                    f"Specified base model `{model_name}` could not be loaded. If this is a private repository, make "
+                    f"sure to set HUGGING_FACE_HUB_TOKEN in your environment. Check that {model_name} is a valid "
+                    "pretrained CausalLM listed on huggingface or a valid local directory containing the weights for a "
+                    "pretrained CausalLM from huggingface. See: "
+                    "https://huggingface.co/models?pipeline_tag=text-generation&sort=downloads for a full list."
                 )
         raise ValidationError(
             f"`base_model` should be a string, instead given: {model_name}. This can be a preset or any pretrained "