diff --git a/app/scodoc/notes_table.py b/app/scodoc/notes_table.py
index 27617c00b..9f9314e2f 100644
--- a/app/scodoc/notes_table.py
+++ b/app/scodoc/notes_table.py
@@ -631,7 +631,7 @@ class NotesTable(object):
                         matiere_sum_coefs += coef
                         matiere_id_last = matiere_id
                     except TypeError:  # val == "NI" "NA"
-                        assert val == "NI" or val == "NA"
+                        assert val == "NI" or val == "NA" or val == "ERR"
                         nb_missing = nb_missing + 1
                         coefs.append(0)
                         coefs_mask.append(0)