diff --git a/backend/src/main/java/org/conferatus/timetable/backend/services/AudienceService.java b/backend/src/main/java/org/conferatus/timetable/backend/services/AudienceService.java
index 1fdae1b..fd6ecef 100644
--- a/backend/src/main/java/org/conferatus/timetable/backend/services/AudienceService.java
+++ b/backend/src/main/java/org/conferatus/timetable/backend/services/AudienceService.java
@@ -64,7 +64,8 @@ public Audience getAudience(User user, String name) {
 
     public List<Audience> getAllAudiences(University university) {
         return audienceRepository.findAll().stream()
-                .filter(it -> Objects.equals(it.getUniversity().id(), university.id())).toList();
+                .filter(it -> it.getUniversity().id() != null && Objects.equals(it.getUniversity().id(),
+                        university.id())).toList();
     }
 
     public Audience addAudience(University university, String audienceName, AudienceType audienceType,
diff --git a/backend/src/main/java/org/conferatus/timetable/backend/services/StudyGroupService.java b/backend/src/main/java/org/conferatus/timetable/backend/services/StudyGroupService.java
index 522bebb..e873147 100644
--- a/backend/src/main/java/org/conferatus/timetable/backend/services/StudyGroupService.java
+++ b/backend/src/main/java/org/conferatus/timetable/backend/services/StudyGroupService.java
@@ -88,6 +88,7 @@ public StudyGroup deleteGroupOrThrow(User user, String groupName) {
 
     public List<StudyGroup> getAllGroups(University university) {
         return studyGroupRepository.findAll()
-                .stream().filter(it -> Objects.equals(it.getUniversity().id(), university.id())).toList();
+                .stream().filter(it -> it.getUniversity().id() != null && Objects.equals(it.getUniversity().id(),
+                        university.id())).toList();
     }
 }
diff --git a/backend/src/main/java/org/conferatus/timetable/backend/services/TeacherService.java b/backend/src/main/java/org/conferatus/timetable/backend/services/TeacherService.java
index 4fd60c1..167f475 100644
--- a/backend/src/main/java/org/conferatus/timetable/backend/services/TeacherService.java
+++ b/backend/src/main/java/org/conferatus/timetable/backend/services/TeacherService.java
@@ -1,7 +1,6 @@
 package org.conferatus.timetable.backend.services;
 
 import java.util.List;
-import java.util.Objects;
 
 import lombok.RequiredArgsConstructor;
 import org.conferatus.timetable.backend.dto.TeacherWishDto;
@@ -61,7 +60,7 @@ public Teacher getTeacher(User user, String name) {
 
     public List<Teacher> getAllTeachers(University university) {
         return teacherRepository.findAll().stream()
-                .filter(it -> Objects.equals(it.getUniversity().id(), university.id())).toList();
+                .filter(it -> it.getUniversity() != null && it.getUniversity().id() == university.id()).toList();
     }
 
     public Teacher addTeacher(User user, String teacherName) {