I have other similar endpoints for testing; that's why, if not, there is no error at this level. Even with the two endpoints, I get the same error. One clarification: I built my ML model with scikit-learn pipeline and Optuna. Now, by building another simple model without Optuna and the preprocessing pipeline with scikit-learn, that is, by simply using, for example, LogisticRegression().fit(X, y), I do not encounter any error for serving with clearml-serving; the request via its endpoint gives me the prediction. Is it not possible to serve a model with preprocessing pipeline from scikit-learn using clearml-serving?