diff --git a/tournaments/models/group_stage.py b/tournaments/models/group_stage.py
index a47eedf..5e7b154 100644
--- a/tournaments/models/group_stage.py
+++ b/tournaments/models/group_stage.py
@@ -34,7 +34,10 @@ class GroupStage(SideStoreModel):
         super().save(*args, **kwargs)
 
     def get_tournament_id(self):
-        return self.tournament.id
+        if self.tournament:
+            return self.tournament.id
+        else:
+            return None
 
     def display_name(self):
         if self.name:
diff --git a/tournaments/models/match.py b/tournaments/models/match.py
index 110bd84..b8afac8 100644
--- a/tournaments/models/match.py
+++ b/tournaments/models/match.py
@@ -46,11 +46,16 @@ class Match(SideStoreModel):
     def tournament(self):
         if self.round:
             return self.round.tournament
-        else:
+        elif self.group_stage:
             return self.group_stage.tournament
+        return None
 
     def get_tournament_id(self):
-        return self.tournament().id
+        tournament = self.tournament()
+        if tournament:
+            return tournament.id
+        else:
+            return None
 
     def court_name(self, index):
         club = None
diff --git a/tournaments/models/player_registration.py b/tournaments/models/player_registration.py
index 86505bd..e23be85 100644
--- a/tournaments/models/player_registration.py
+++ b/tournaments/models/player_registration.py
@@ -49,7 +49,10 @@ class PlayerRegistration(SideStoreModel):
         super().save(*args, **kwargs)
 
     def get_tournament_id(self):
-        return self.team_registration.tournament.id
+        if self.team_registration and self.team_registration.tournament:
+            return self.team_registration.tournament.id
+        else:
+            return None
 
     def name(self):
         return f"{self.first_name} {self.last_name}"
diff --git a/tournaments/models/round.py b/tournaments/models/round.py
index 352435b..a6c0250 100644
--- a/tournaments/models/round.py
+++ b/tournaments/models/round.py
@@ -31,7 +31,10 @@ class Round(SideStoreModel):
         super().save(*args, **kwargs)
 
     def get_tournament_id(self):
-        return self.tournament.id
+        if self.tournament:
+            return self.tournament.id
+        else:
+            return None
 
     def name(self):
         if self.parent and self.parent.parent is None:
diff --git a/tournaments/models/team_registration.py b/tournaments/models/team_registration.py
index 28fcf29..f4abfd0 100644
--- a/tournaments/models/team_registration.py
+++ b/tournaments/models/team_registration.py
@@ -50,7 +50,10 @@ class TeamRegistration(SideStoreModel):
         super().save(*args, **kwargs)
 
     def get_tournament_id(self):
-        return self.tournament.id
+        if self.tournament:
+            return self.tournament.id
+        else:
+            return None
 
     def player_names_as_list(self):
         players = list(self.player_registrations.all())
diff --git a/tournaments/models/team_score.py b/tournaments/models/team_score.py
index 0d87dbc..078f015 100644
--- a/tournaments/models/team_score.py
+++ b/tournaments/models/team_score.py
@@ -14,7 +14,10 @@ class TeamScore(SideStoreModel):
         pass
 
     def __str__(self):
-        return f"{self.match.stage_name()} #{self.match.index}: {self.player_names()}"
+        if self.match:
+            return f"{self.match.stage_name()} #{self.match.index}: {self.player_names()}"
+        else:
+            return "Empty"
 
     def save(self, *args, **kwargs):
         self.store_id = str(self.get_tournament_id())
@@ -29,7 +32,11 @@ class TeamScore(SideStoreModel):
             return None
 
     def get_tournament_id(self):
-        return self.tournament().id
+        tournament = self.tournament()
+        if tournament:
+            return tournament.id
+        else:
+            return None
 
     def player_names(self):
         if self.team_registration:
diff --git a/tournaments/signals.py b/tournaments/signals.py
index f991688..70c85e3 100644
--- a/tournaments/signals.py
+++ b/tournaments/signals.py
@@ -91,6 +91,8 @@ def notify_team(team, tournament, message_type):
 
 @receiver(pre_delete, sender=TeamRegistration)
 def unregister_team(sender, instance, **kwargs):
+    if not instance.tournament:
+        return
     if instance.tournament.is_deleted:
         return
     if instance.tournament.enable_online_registration is False:
@@ -157,7 +159,7 @@ def check_waiting_list(sender, instance, **kwargs):
 
 @receiver(pre_save, sender=TeamRegistration)
 def warn_team_walkout_status_change(sender, instance, **kwargs):
-    if instance.id is None or instance.tournament.enable_online_registration is False:
+    if instance.id is None or instance.tournament is None or instance.tournament.enable_online_registration is False:
         return
 
     previous_instance = None