File "electrum\gui\qt\network_dialog.py", line 468, in set_server
  File "electrum\network.py", line 299, in run_from_another_thread
  File "concurrent\futures\_base.py", line 432, in result
  File "concurrent\futures\_base.py", line 384, in __get_result
  File "electrum\util.py", line 934, in wrapper
  File "electrum\network.py", line 617, in set_parameters
  File "electrum\network.py", line 635, in switch_lagging_interface
  File "electrum\blockchain.py", line 186, in func_wrapper
  File "electrum\blockchain.py", line 462, in read_header