diff --git a/frontend/src/OnlineClassroom/ClassroomUserCreation.tsx b/frontend/src/OnlineClassroom/ClassroomUserCreation.tsx
index ed0bc51..f2fa364 100644
--- a/frontend/src/OnlineClassroom/ClassroomUserCreation.tsx
+++ b/frontend/src/OnlineClassroom/ClassroomUserCreation.tsx
@@ -31,7 +31,7 @@ export function ClassroomUserCreation(props: {
         const paternalSurname = props.person.person_paternal_surname;
         const maternalSurname = props.person.person_maternal_surname;
 
-        const user = `${firstName[0]}${secondName[0] ?? ""}${paternalSurname}${maternalSurname[0]}`;
+        const user = `${firstName[0]}${secondName?.[0] ?? ""}${paternalSurname}${maternalSurname[0]}`;
 
         const next_date = new Date();
         next_date.setDate(next_date.getDate() + 60);
@@ -64,7 +64,7 @@ export function ClassroomUserCreation(props: {
                     );
                 } else {
                     console.error(response.data);
-                    setError(response.data.Err.reason);
+                    setError(response.data.Error.reason);
                     setStatus(LoadingStatus.Error);
                 }
             })