diff --git a/src/app/api/replies/route.ts b/src/app/api/replies/route.ts
index 310a1b25..a2cfea65 100644
--- a/src/app/api/replies/route.ts
+++ b/src/app/api/replies/route.ts
@@ -58,15 +58,18 @@ export async function GET(req: Request) {
         }
 
         if (doubt.type === 'teacher') {
-            const [membership] = await db
-            .select()
-            .from(membershipsTable)
-            .where(
-                and(
-                    eq(membershipsTable.userEmail, email),
-                    eq(membershipsTable.classroomId, doubt.classroomId!)
-                )
-            );
+        if (!doubt.classroomId) {
+            return errorResponse("Access denied", 403);
+        }
+        const [membership] = await db
+        .select()
+        .from(membershipsTable)
+        .where(
+            and(
+                eq(membershipsTable.userEmail, email!),
+                eq(membershipsTable.classroomId, doubt.classroomId)
+            )
+        );
 
                 const isTeacher = membership ? canTeach(membership.role) : false;
                 const isOwner = doubt.userEmail === email;
diff --git a/src/components/AskDoubt.tsx b/src/components/AskDoubt.tsx
index e88c9413..10244340 100644
--- a/src/components/AskDoubt.tsx
+++ b/src/components/AskDoubt.tsx
@@ -418,6 +418,9 @@ export default function AskDoubt({ defaultSubject = "", isOpen, onClose, onSucce
                             className="w-full bg-slate-100 dark:bg-white/5 border border-slate-200 dark:border-white/10 rounded-2xl p-4 text-slate-900 dark:text-white focus:outline-none focus:border-blue-500/50 font-bold text-sm"
                             required
                         />
+                        {subjectWasEdited && !subject.trim() && (
+                        <p className="text-red-400 text-xs font-semibold px-1 mt-1">Subject is required.</p>
+                        )}
                         {suggestedSubject && (
                             <div className="flex items-center gap-2 px-1 text-[10px] font-bold uppercase tracking-widest text-blue-300">
                                 <Sparkles className="w-3 h-3" />