File "site-packages\electrum-3.1.2-py3.5.egg\electrum_gui\qt\network_dialog.py", line 446, in set_server
  File "site-packages\electrum-3.1.2-py3.5.egg\electrum\network.py", line 469, in set_parameters
  File "site-packages\electrum-3.1.2-py3.5.egg\electrum\network.py", line 484, in switch_lagging_interface
  File "site-packages\electrum-3.1.2-py3.5.egg\electrum\blockchain.py", line 259, in read_header