diff --git a/mastodon/auth.py b/mastodon/auth.py
index 46b3fdc4..d1cc21fd 100644
--- a/mastodon/auth.py
+++ b/mastodon/auth.py
@@ -91,7 +91,7 @@ class OAuth2Backend(ModelBackend):
 
         # when username is provided, assume that token is newly obtained and valid
         try:
-            user = UserModel._default_manager.filter(username=username, mastodon_site=site)
+            user = UserModel._default_manager.get(username=username, mastodon_site=site)
         except UserModel.DoesNotExist:
             return None
         else:
diff --git a/sync/apps.py b/sync/apps.py
index 122f3d33..14518e54 100644
--- a/sync/apps.py
+++ b/sync/apps.py
@@ -7,5 +7,4 @@ class SyncConfig(AppConfig):
 
     def ready(self):
         from sync.jobs import sync_task_manager
-        if settings.START_SYNC:
-            sync_task_manager.start()
\ No newline at end of file
+        sync_task_manager.start()
\ No newline at end of file
diff --git a/sync/jobs.py b/sync/jobs.py
index 0b43c902..519b8618 100644
--- a/sync/jobs.py
+++ b/sync/jobs.py
@@ -7,6 +7,7 @@ import threading
 import time
 from dataclasses import dataclass
 from datetime import datetime
+from django.conf import settings
 from django.utils import timezone
 from django.core.exceptions import ObjectDoesNotExist
 from openpyxl import load_workbook
@@ -73,7 +74,8 @@ class SyncTaskManger:
         return self.__stop_event.is_set()
 
     def start(self):
-        self.__enqueue_existing_tasks()  # enqueue
+        if settings.START_SYNC:
+            self.__enqueue_existing_tasks()  # enqueue
 
         listen_new_task_thread = threading.Thread(
             target=self.__listen_for_new_task, daemon=True)