File "/usr/lib/python3/dist-packages/electrum/gui/qt/network_dialog.py", line 394, in set_server
    self.network.run_from_another_thread(self.network.set_parameters(net_params))
  File "/usr/lib/python3/dist-packages/electrum/network.py", line 374, in run_from_another_thread
    return fut.result(timeout)
  File "/usr/lib/python3.9/concurrent/futures/_base.py", line 440, in result
    return self.__get_result()
  File "/usr/lib/python3.9/concurrent/futures/_base.py", line 389, in __get_result
    raise self._exception
  File "/usr/lib/python3/dist-packages/electrum/util.py", line 1056, in wrapper
    return await func(*args, **kwargs)
  File "/usr/lib/python3/dist-packages/electrum/network.py", line 601, in set_parameters
    self.config.set_key('server', str(server), True)
  File "/usr/lib/python3/dist-packages/electrum/simple_config.py", line 160, in set_key
    self._set_key_in_user_config(key, value, save)
  File "/usr/lib/python3/dist-packages/electrum/simple_config.py", line 169, in _set_key_in_user_config
    self.save_user_config()
  File "/usr/lib/python3/dist-packages/electrum/simple_config.py", line 261, in save_user_config
    with open(path, "w", encoding='utf-8') as f: