diff --git a/pyproject.toml b/pyproject.toml
index 47701fb..7d0ce3b 100644
--- a/pyproject.toml
+++ b/pyproject.toml
@@ -4,7 +4,7 @@ build-backend = "hatchling.build"
 
 [project]
 name = "tabpfn-client"
-version = "0.0.15"
+version = "0.0.20"
 requires-python = ">=3.10"
 dependencies = [
     "httpx>=0.24.1",
diff --git a/tabpfn_client/client.py b/tabpfn_client/client.py
index 4fe1c4c..21d2a9d 100644
--- a/tabpfn_client/client.py
+++ b/tabpfn_client/client.py
@@ -160,7 +160,9 @@ def predict(
         return result
 
     @staticmethod
-    def _validate_response(response, method_name, only_version_check=False):
+    def _validate_response(
+        response: httpx.Response, method_name, only_version_check=False
+    ):
         # If status code is 200, no errors occurred on the server side.
         if response.status_code == 200:
             return
@@ -170,11 +172,11 @@ def _validate_response(response, method_name, only_version_check=False):
         try:
             load = response.json()
         except json.JSONDecodeError as e:
-            logging.error(f"Failed to parse JSON from response in {method_name}: {e}")
+            logging.info(f"Failed to parse JSON from response in {method_name}: {e}")
 
         # Check if the server requires a newer client version.
         if response.status_code == 426:
-            logger.error(
+            logger.info(
                 f"Fail to call {method_name}, response status: {response.status_code}"
             )
             raise RuntimeError(load.get("detail"))
@@ -186,20 +188,34 @@ def _validate_response(response, method_name, only_version_check=False):
             logger.error(
                 f"Fail to call {method_name}, response status: {response.status_code}"
             )
-            if (
-                len(
-                    reponse_split_up := response.text.split(
-                        "The following exception has occurred:"
+            try:
+                if (
+                    len(
+                        reponse_split_up := response.text.split(
+                            "The following exception has occurred:"
+                        )
                     )
-                )
-                > 1
-            ):
-                raise RuntimeError(
-                    f"Fail to call {method_name} with error: {reponse_split_up[1]}"
-                )
+                    > 1
+                ):
+                    relevant_reponse_text = reponse_split_up[1].split(
+                        "debug_error_string"
+                    )[0]
+                    if "ValueError" in relevant_reponse_text:
+                        # Extract the ValueError message
+                        value_error_msg = relevant_reponse_text.split(
+                            "ValueError. Arguments: ("
+                        )[1].split(",)")[0]
+                        # Remove extra quotes and spaces
+                        value_error_msg = value_error_msg.strip("'")
+                        # Raise the ValueError with the extracted message
+                        raise ValueError(value_error_msg)
+                    raise RuntimeError(relevant_reponse_text)
+            except Exception as e:
+                if isinstance(e, (ValueError, RuntimeError)):
+                    raise e
             raise RuntimeError(
-                f"Fail to call {method_name} with error: {response.status_code} and reason: "
-                f"{response.reason_phrase}"
+                f"Fail to call {method_name} with error: {response.status_code}, reason: "
+                f"{response.reason_phrase} and text: {response.text}"
             )
 
     def try_connection(self) -> bool:
diff --git a/tabpfn_client/estimator.py b/tabpfn_client/estimator.py
index 7d043b7..65f061f 100644
--- a/tabpfn_client/estimator.py
+++ b/tabpfn_client/estimator.py
@@ -182,10 +182,23 @@ def __init__(
         self.add_fingerprint_features = add_fingerprint_features
         self.subsample_samples = subsample_samples
 
+    def _validate_targets_and_classes(self, y) -> np.ndarray:
+        from sklearn.utils import column_or_1d
+        from sklearn.utils.multiclass import check_classification_targets
+
+        y_ = column_or_1d(y, warn=True)
+        check_classification_targets(y)
+
+        # Get classes and encode before type conversion to guarantee correct class labels.
+        not_nan_mask = ~np.isnan(y)
+        self.classes_ = np.unique(y_[not_nan_mask])
+
     def fit(self, X, y):
         # assert init() is called
         init()
 
+        self._validate_targets_and_classes(y)
+
         if config.g_tabpfn_config.use_server:
             try:
                 assert (
@@ -203,7 +216,9 @@ def fit(self, X, y):
 
     def predict(self, X):
         probas = self.predict_proba(X)
-        return np.argmax(probas, axis=1)
+        y = np.argmax(probas, axis=1)
+        y = self.classes_.take(np.asarray(y, dtype=int))
+        return y
 
     def predict_proba(self, X):
         check_is_fitted(self)