diff --git a/pina/geometry/ellipsoid.py b/pina/geometry/ellipsoid.py
index 8eb9885..d9c3680 100644
--- a/pina/geometry/ellipsoid.py
+++ b/pina/geometry/ellipsoid.py
@@ -281,4 +281,4 @@ class EllipsoidDomain(Location):
         if mode in ['random']:
             return _Nd_sampler(n, mode, variables)
         else:
-            raise NotImplemented(f'mode={mode} is not implemented.')
+            raise NotImplementedError(f'mode={mode} is not implemented.')