File "/usr/lib/python3/dist-packages/electrum/gui/qt/network_dialog.py", line 447, in set_server
    self.network.set_parameters(host, port, protocol, proxy, auto_connect)
  File "/usr/lib/python3/dist-packages/electrum/network.py", line 547, in set_parameters
    self.switch_lagging_interface()
  File "/usr/lib/python3/dist-packages/electrum/network.py", line 251, in func_wrapper
    return func(self, *args, **kwargs)
  File "/usr/lib/python3/dist-packages/electrum/network.py", line 563, in switch_lagging_interface
    header = self.blockchain().read_header(self.get_local_height())
  File "/usr/lib/python3/dist-packages/electrum/blockchain.py", line 295, in read_header
    self.assert_headers_file_available(name)
  File "/usr/lib/python3/dist-packages/electrum/blockchain.py", line 259, in assert_headers_file_available
    raise FileNotFoundError('Cannot find headers file but headers_dir is there. Should be at {}'.format(path))