diff --git a/services/headless-lms/models/src/library/peer_or_self_reviewing.rs b/services/headless-lms/models/src/library/peer_or_self_reviewing.rs
index 5c08c0d7cd5..dd8693e48a0 100644
--- a/services/headless-lms/models/src/library/peer_or_self_reviewing.rs
+++ b/services/headless-lms/models/src/library/peer_or_self_reviewing.rs
@@ -521,6 +521,11 @@ async fn try_to_select_peer_review_candidate_from_queue(
                 .await
                 .optional()?;
             if let Some(ess) = ess {
+                // Peer reviewing only works if there is a course_id and a course instance id in it.
+                if ess.course_id.is_none() || ess.course_instance_id.is_none() {
+                    warn!(exercise_slide_submission_id = %ess_id, "Selected exercise slide submission that doesn't have a course_id or course_instance_id. Skipping it.");
+                    continue;
+                };
                 if ess.deleted_at.is_none() {
                     return Ok(Some(ess));
                 }
diff --git a/services/headless-lms/server/src/controllers/course_material/exercises.rs b/services/headless-lms/server/src/controllers/course_material/exercises.rs
index 85a63b9b045..9a2ef9bd9b0 100644
--- a/services/headless-lms/server/src/controllers/course_material/exercises.rs
+++ b/services/headless-lms/server/src/controllers/course_material/exercises.rs
@@ -317,20 +317,47 @@ async fn submit_peer_or_self_review(
             payload.exercise_slide_submission_id,
         )
         .await?;
-    let receiver_user_exercise_state = user_exercise_states::get_users_current_by_exercise(
-        &mut conn,
-        exercise_slide_submission.user_id,
-        &exercise,
-    )
-    .await?;
-    models::library::peer_or_self_reviewing::create_peer_or_self_review_submission_for_user(
-        &mut conn,
-        &exercise,
-        giver_user_exercise_state,
-        receiver_user_exercise_state,
-        payload.0,
-    )
-    .await?;
+
+    if let Some(receiver_course_instance_id) = exercise_slide_submission.course_instance_id {
+        let receiver_user_exercise_state = user_exercise_states::get_user_exercise_state_if_exists(
+            &mut conn,
+            exercise_slide_submission.user_id,
+            exercise.id,
+            user_exercise_states::CourseInstanceOrExamId::Instance(receiver_course_instance_id),
+        )
+        .await?;
+        if let Some(receiver_user_exercise_state) = receiver_user_exercise_state {
+            models::library::peer_or_self_reviewing::create_peer_or_self_review_submission_for_user(
+            &mut conn,
+            &exercise,
+            giver_user_exercise_state,
+            receiver_user_exercise_state,
+            payload.0,
+        )
+        .await?;
+        } else {
+            warn!(
+                "No user exercise state found for receiver's exercise slide submission id: {}",
+                exercise_slide_submission.id
+            );
+            return Err(ControllerError::new(
+                ControllerErrorType::BadRequest,
+                "No user exercise state found for receiver's exercise slide submission."
+                    .to_string(),
+                None,
+            ));
+        }
+    } else {
+        warn!(
+            "No course instance id found for receiver's exercise slide submission id: {}",
+            exercise_slide_submission.id
+        );
+        return Err(ControllerError::new(
+            ControllerErrorType::BadRequest,
+            "No course instance id found for receiver's exercise slide submission.".to_string(),
+            None,
+        ));
+    }
     let token = skip_authorize();
     token.authorized_ok(web::Json(true))
 }