diff --git a/python/sdist/amici/jax/petab.py b/python/sdist/amici/jax/petab.py
index 4d1cfd303a..0bf0d97696 100644
--- a/python/sdist/amici/jax/petab.py
+++ b/python/sdist/amici/jax/petab.py
@@ -320,6 +320,11 @@ def _get_nominal_parameter_values(
         ), model
 
     def _get_inputs(self):
+        if (
+            self._petab_problem.mapping_df is None
+            or "netId" not in self._petab_problem.mapping_df.columns
+        ):
+            return {}
         inputs = {
             net: {} for net in self._petab_problem.mapping_df["netId"].unique()
         }