FlexGet version: always up2date
Python version: 3.6
Installation method: pip
Using daemon (yes/no): no
OS and version: ubuntu 18.04
Additional information: error happens after hundreds of successes .. but constantly.

2019-12-25 23:06:55 CRITICAL task          Usenet_movies_Search BUG: Unhandled error in plugin discover: 'NoneType' object has no attribute 'replace'
Traceback (most recent call last):
  File "/usr/lib/python3.6/threading.py", line 884, in _bootstrap
    self._bootstrap_inner()
    |    -> <function Thread._bootstrap_inner at 0x7f4842a289d8>
    -> <Thread(task_queue, started daemon 139948162770688)>
  File "/usr/lib/python3.6/threading.py", line 916, in _bootstrap_inner
    self.run()
    |    -> <function Thread.run at 0x7f4842a287b8>
    -> <Thread(task_queue, started daemon 139948162770688)>
  File "/usr/lib/python3.6/threading.py", line 864, in run
    self._target(*self._args, **self._kwargs)
    |    |        |    |        |    -> {}
    |    |        |    |        -> <Thread(task_queue, started daemon 139948162770688)>
    |    |        |    -> ()
    |    |        -> <Thread(task_queue, started daemon 139948162770688)>
    |    -> <bound method TaskQueue.run of <flexget.task_queue.TaskQueue object at 0x7f483952e3c8>>
    -> <Thread(task_queue, started daemon 139948162770688)>

  File "/usr/local/lib/python3.6/dist-packages/flexget/task_queue.py", line 45, in run
    self.current_task.execute()
    |    |            -> <function Task.execute at 0x7f483ce47c80>
    |    -> <flexget.task.Task object at 0x7f4838ec6da0>
    -> <flexget.task_queue.TaskQueue object at 0x7f483952e3c8>

  File "/usr/local/lib/python3.6/dist-packages/flexget/task.py", line 79, in wrapper
    return func(self, *args, **kw)
           |    |      |       -> {}
           |    |      -> ()
           |    -> <flexget.task.Task object at 0x7f4838ec6da0>
           -> <function Task.execute at 0x7f483ce47bf8>

  File "/usr/local/lib/python3.6/dist-packages/flexget/task.py", line 696, in execute
    self._execute()
    |    -> <function Task._execute at 0x7f483ce47b70>
    -> <flexget.task.Task object at 0x7f4838ec6da0>

  File "/usr/local/lib/python3.6/dist-packages/flexget/task.py", line 662, in _execute
    self.__run_task_phase(phase)
    |                     -> 'input'
    -> <flexget.task.Task object at 0x7f4838ec6da0>

  File "/usr/local/lib/python3.6/dist-packages/flexget/task.py", line 488, in __run_task_phase
    response = self.__run_plugin(plugin, phase, args)
               |                 |       |      -> (<flexget.task.Task object at 0x7f4838ec6da0>, {'what': [{'movie_list': 'Default'}], 'from': [{'newznab': {'website': 'https:...
               |                 |       -> 'input'
               |                 -> <PluginInfo(name=discover)>
               -> <flexget.task.Task object at 0x7f4838ec6da0>

> File "/usr/local/lib/python3.6/dist-packages/flexget/task.py", line 521, in __run_plugin
    result = method(*args, **kwargs)
             |       |       -> {}
             |       -> (<flexget.task.Task object at 0x7f4838ec6da0>, {'what': [{'movie_list': 'Default'}], 'from': [{'newznab': {'website': 'https:...
             -> <Event(name=plugin.discover.input,func=on_task_input,priority=128)>

  File "/usr/local/lib/python3.6/dist-packages/flexget/event.py", line 20, in __call__
    return self.func(*args, **kwargs)
           |    |     |       -> {}
           |    |     -> (<flexget.task.Task object at 0x7f4838ec6da0>, {'what': [{'movie_list': 'Default'}], 'from': [{'newznab': {'website': 'https:...
           |    -> <bound method Discover.on_task_input of <flexget.plugins.input.discover.Discover object at 0x7f483bbdb4a8>>
           -> <Event(name=plugin.discover.input,func=on_task_input,priority=128)>

  File "/usr/local/lib/python3.6/dist-packages/flexget/plugins/input/discover.py", line 290, in on_task_input
    return self.execute_searches(config, entries, task)
           |    |                |       |        -> <flexget.task.Task object at 0x7f4838ec6da0>
           |    |                |       -> [<Entry(title=The Professor (2019),state=undecided)>, <Entry(title=Das hält kein Jahr ..! (2013),state=undecided)>, <Entry(ti...
           |    |                -> {'what': [{'movie_list': 'Default'}], 'from': [{'newznab': {'website': 'https://scenenzb.com', 'apikey': '2cab77fa83b00a8775f...
           |    -> <function Discover.execute_searches at 0x7f483bf7fea0>
           -> <flexget.plugins.input.discover.Discover object at 0x7f483bbdb4a8>

  File "/usr/local/lib/python3.6/dist-packages/flexget/plugins/input/discover.py", line 132, in execute_searches
    search_results = search.search(task=task, entry=entry, config=plugin_config)
                     |      |           |           |             -> {'website': 'https://scenenzb.com', 'apikey': '2cab77fa83b00a8775f429406472f9f4', 'category': 'movie', 'url': 'https://scenen...
                     |      |           |           -> <Entry(title=The Lord of the Rings: The Two Towers (Extended) (2002),state=undecided)>
                     |      |           -> <flexget.task.Task object at 0x7f4838ec6da0>
                     |      -> <function Newznab.search at 0x7f4839f7c840>
                     -> <flexget.components.sites.sites.newznab.Newznab object at 0x7f483960e128>

  File "/usr/local/lib/python3.6/dist-packages/flexget/components/sites/sites/newznab.py", line 87, in search
    return self.do_search_movie(entry, task, config)
           |    |               |      |     -> {'website': 'https://scenenzb.com', 'apikey': '2cab77fa83b00a8775f429406472f9f4', 'category': 'movie', 'url': 'https://scenen...
           |    |               |      -> <flexget.task.Task object at 0x7f4838ec6da0>
           |    |               -> <Entry(title=The Lord of the Rings: The Two Towers (Extended) (2002),state=undecided)>
           |    -> <function Newznab.do_search_movie at 0x7f4839f7c950>
           -> <flexget.components.sites.sites.newznab.Newznab object at 0x7f483960e128>

  File "/usr/local/lib/python3.6/dist-packages/flexget/components/sites/sites/newznab.py", line 122, in do_search_movie
    imdb_id = arg_entry['imdb_id'].replace('tt', '')
              -> <Entry(title=The Lord of the Rings: The Two Towers (Extended) (2002),state=undecided)>

AttributeError: 'NoneType' object has no attribute 'replace'
2019-12-25 23:06:56 CRITICAL manager       Usenet_movies_Search An unexpected crash has occurred. Writing crash report to /home/snikay/.flexget/crash_report.2019.12.25.230656135181.log. Please verify you are running the latest version of flexget by using "flexget -V" from CLI or by using version_checker plugin at http://flexget.com/wiki/Plugins/version_checker. You are currently using version 3.0.23
2019-12-25 23:06:56 WARNING  task          Usenet_movies_Search Aborting task (plugin: discover)