Traceback (most recent call last):
  File "electrum\gui\qt\send_tab.py", line 570, in do_pay_or_get_invoice
  File "electrum\gui\qt\send_tab.py", line 597, in do_pay_invoice
  File "electrum\gui\qt\send_tab.py", line 319, in pay_onchain_dialog
  File "electrum\gui\qt\confirm_tx_dialog.py", line 622, in __init__
  File "electrum\gui\qt\util.py", line 376, in __init__
  File "electrum\gui\qt\confirm_tx_dialog.py", line 125, in update
  File "electrum\gui\qt\confirm_tx_dialog.py", line 525, in _update_widgets
  File "electrum\gui\qt\confirm_tx_dialog.py", line 673, in can_pay_assuming_zero_fees
  File "electrum\gui\qt\send_tab.py", line 311, in <lambda>
  File "electrum\util.py", line 481, in do_profile
  File "electrum\wallet.py", line 1872, in make_unsigned_transaction
TypeError: conversion from NoneType to Decimal is not supported