General system exception - notifications (email) fail to send

[OmarWazzan]

Describe the bug
(1) General system error appears in logs
(2) When trying to send an email notification, error ResponseError: Response returned an error code appears. No error appears on logs, but one does on terminal.

To Reproduce
Steps to reproduce the behavior:
General system error: No steps, just appears in logs
Notifications: Go to notification transport (email), test / Use email flow

Logs
General system exception:

Stacktrace from authentik

Traceback (most recent call last):
  File "/ak-root/venv/lib/python3.12/site-packages/celery/app/trace.py", line 545, in trace_task
    task_after_return(
  File "/authentik/events/system_tasks.py", line 86, in after_return
    DBSystemTask.objects.update_or_create(
  File "/ak-root/venv/lib/python3.12/site-packages/django/db/models/manager.py", line 87, in manager_method
    return getattr(self.get_queryset(), name)(*args, **kwargs)
           ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
  File "/ak-root/venv/lib/python3.12/site-packages/django/db/models/query.py", line 986, in update_or_create
    obj, created = self.select_for_update().get_or_create(
                   ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
  File "/ak-root/venv/lib/python3.12/site-packages/django/db/models/query.py", line 948, in get_or_create
    return self.get(**kwargs), False
           ^^^^^^^^^^^^^^^^^^
  File "/ak-root/venv/lib/python3.12/site-packages/django/db/models/query.py", line 652, in get
    raise self.model.MultipleObjectsReturned(
authentik.events.models.MultipleObjectsReturned: get() returned more than one SystemTask -- it returned 2!

Email test:
{"event": "Booting worker with pid: 35873", "level": "info", "logger": "gunicorn.error", "timestamp": 1736950968.107592}
{"event": "Internal Server Error: /api/v3/events/transports/1c1abc03-c569-4c46-908e-f2152509d11e/test/", "level": "error", "logger": "django.request", "timestamp": 1736974667.2981143}
2025-01-14 23:41:29 [info ] waiting to acquire database lock
2025-01-14 23:41:29 [info ] applying django migrations

Version and Deployment (please complete the following information):

• authentik version: 2024.12.2
• Deployment: [e.g. docker-compose, helm]

Additional context
Add any other context about the problem here.