KeyError: 'symbol'
File "./gns3-server\gns3server\web\route.py", line 195, in control_schema
File "C:\Python36-x64\lib\asyncio\coroutines.py", line 210, in coro
File "./gns3-server\gns3server\handlers\api\controller\appliance_handler.py", line 51, in list
File "./gns3-server\gns3server\web\response.py", line 104, in json
File "./gns3-server\gns3server\controller\appliance.py", line 81, in __json__
KeyError: 'symbol'
https://sentry.io/gns3/gns3-server/issues/300501034/