diff --git a/midas/checker/frames/column_groupby_methods.py b/midas/checker/frames/column_groupby_methods.py
index 920a2b8..c92b08e 100644
--- a/midas/checker/frames/column_groupby_methods.py
+++ b/midas/checker/frames/column_groupby_methods.py
@@ -86,6 +86,9 @@ class ColumnGroupByMethodRegistry(MethodRegistry[Call]):
 
         # TODO: maybe better to filter arguments and pass some, in case the
         # return type depends on them
+
+        # Don't catch UndefinedMethodException because all aggregation
+        # methods should be defined on columns too
         returns: Type = self.typer.call_method(
             location=call.location,
             call_expr=call.call_expr,
diff --git a/midas/checker/frames/frame_groupby_methods.py b/midas/checker/frames/frame_groupby_methods.py
index a2efba6..591c3ac 100644
--- a/midas/checker/frames/frame_groupby_methods.py
+++ b/midas/checker/frames/frame_groupby_methods.py
@@ -53,6 +53,8 @@ class FrameGroupByMethodRegistry(MethodRegistry[Call]):
         for column in call.groupby.frame.columns:
             with self.reporter.with_context(f"in column '{column.name}'"):
                 column_groupby: ColumnGroupBy = ColumnGroupBy(column=column.type)
+                # Don't catch UndefinedMethodException because all aggregation
+                # methods should be defined on columns too
                 result_type: Type = self.typer.call_method(
                     location=call.location,
                     call_expr=call.call_expr,
diff --git a/midas/checker/python.py b/midas/checker/python.py
index b2995d0..dd7eac8 100644
--- a/midas/checker/python.py
+++ b/midas/checker/python.py
@@ -772,14 +772,21 @@ class PythonTyper(
         match expr.callee:
             case p.GetExpr(object=obj, name=method):
                 obj_type: Type = self.type_of(obj)
-                return self.call_method(
-                    location=expr.location,
-                    call_expr=expr,
-                    obj=(obj, obj_type),
-                    method_name=method,
-                    positional=positional,
-                    keywords=keywords,
-                )
+                try:
+                    return self.call_method(
+                        location=expr.location,
+                        call_expr=expr,
+                        obj=(obj, obj_type),
+                        method_name=method,
+                        positional=positional,
+                        keywords=keywords,
+                    )
+                except UndefinedMethodException:
+                    self.reporter.error(
+                        expr.location,
+                        f"Unknown method {method} on type {obj_type}",
+                    )
+                    return UnknownType()
 
         callee: Type = self.type_of(expr.callee)
         result: CallResult = self.dispatcher.get_result(