Error when trying to load trades from Poloniex

[pepae]

I can see the Poloniex balances, but whenever I try to create a tax report, below error occurs.
When I click on trade balances in the UI, nothing happens.

-- ERROR:rotkehlchen.server:Greenlet for task 2 dies with exception: Expected string, int, float, or Decimal to initialize an FVal.Found <class 'str'>..
Exception Name: <class 'ValueError'>
Exception Info: Expected string, int, float, or Decimal to initialize an FVal.Found <class 'str'>.
Traceback:
   File "site-packages/gevent/greenlet.py", line 536, in run
  File "rotkehlchen/server.py", line 93, in _query_async
  File "rotkehlchen/server.py", line 211, in process_trade_history
  File "rotkehlchen/rotkehlchen.py", line 382, in process_history
  File "rotkehlchen/history.py", line 726, in get_history
  File "rotkehlchen/order_formatting.py", line 126, in asset_movements_from_dictlist
  File "rotkehlchen/fval.py", line 54, in __init__

[LefterisJP]

@pepae can you try again with latest master?

[pepae]

@LefterisJP sorry for getting back on this so late. Still same behavior with 0.4.0

[LefterisJP]

Can you try latest master (so build by source) and give me the entire rotkehlchen.log?

[LefterisJP]

@pepae can you tell me if this still happens to you with 1.0.0? And if yes then let's sit side by side and fix this if you can provide logs.

[LefterisJP]

@pepae sent me some logs and in the logs there is a similar error but in a different location:

25/07/2019 11:14:27 W. Europe Daylight Time -- ERROR:rotkehlchen.server:Greenlet for task 4 dies with exception: Invalid type <class 'NoneType'> of data given to FVal constructor.
Exception Name: <class 'ValueError'>
Exception Info: Invalid type <class 'NoneType'> of data given to FVal constructor
Traceback:
   File "src\gevent\greenlet.py", line 716, in gevent._greenlet.Greenlet.run
  File "rotkehlchen\server.py", line 128, in _query_async
  File "rotkehlchen\server.py", line 310, in process_trade_history
  File "rotkehlchen\rotkehlchen.py", line 378, in process_history
  File "rotkehlchen\history.py", line 649, in get_history
  File "rotkehlchen\history.py", line 488, in create_history
  File "rotkehlchen\history.py", line 419, in query_poloniex_history
  File "rotkehlchen\poloniex.py", line 546, in query_deposits_withdrawals
  File "rotkehlchen\fval.py", line 33, in __init__

That can only mean that a query to the poloniex API call returnDepositWithdrawals returns null for the fee field.