small formatting fix

aea/configurations/validation.py

@@ -236,14 +236,17 @@ def _validate(self, instance: Dict) -> None:
         errors: List[jsonschema.ValidationError] = list(
             self._validator.iter_errors(instance=instance)
         )
+
         if len(errors) > 0:
+            error = errors[0]
+            # raise Exception(error.__dict__)
             error_msg = self._build_message_from_errors(errors)
             raise AEAValidationError(f"{error_msg}")
 
     @staticmethod
     def _build_message_from_errors(errors: List[jsonschema.ValidationError]) -> str:
         """Build an error message from validation errors."""
-        path = lambda error: ".".join(list(error.path))  # noqa # type: ignore
+        path = lambda error: "::".join(map(str, error.path))  # noqa # type: ignore
         result = [f"{path(error)}: {error.message}" for error in errors]
         return "The following errors occurred during validation:\n - " + "\n - ".join(
             result