Critical failure

CRITICAL
Failed to check for alert VolumeStatus: Traceback (most recent call last): File "/usr/local/lib/python3.8/site-packages/middlewared/plugins/alert.py", line 706, in __run_source alerts = (await alert_source.check()) or [] File "/usr/local/lib/python3.8/site-packages/middlewared/alert/source/volume_status.py", line 31, in check for vdev in await self.middleware.call("pool.flatten_topology", pool["topology"]): File "/usr/local/lib/python3.8/site-packages/middlewared/main.py", line 1238, in call return await self._call( File "/usr/local/lib/python3.8/site-packages/middlewared/main.py", line 1206, in _call return await self.run_in_executor(prepared_call.executor, methodobj, *prepared_call.args) File "/usr/local/lib/python3.8/site-packages/middlewared/main.py", line 1110, in run_in_executor return await loop.run_in_executor(pool, functools.partial(method, *args, **kwargs)) File "/usr/local/lib/python3.8/site-packages/middlewared/utils/io_thread_pool_executor.py", line 25, in run result = self.fn(*self.args, **self.kwargs) File "/usr/local/lib/python3.8/site-packages/middlewared/plugins/pool.py", line 438, in flatten_topology d = deque(sum(topology.values(), [])) AttributeError: 'NoneType' object has no attribute 'values'
2021-03-02 19:54:35 (America/Denver)