Auto connect to open network failing

[TilCreator]

When I tested the WiFiManager it failed while trying to connect to an open WiFi:

ssid: openWifi chan: 11 rssi: -36 authmode: open
Trying to connect to openWifi...
Traceback (most recent call last):
  File "main.py", line 4, in <module>
  File "wifimgr.py", line 57, in get_connection
  File "wifimgr.py", line 52, in get_connection
  File "wifimgr.py", line 89, in do_connect
TypeError: can't convert 'NoneType' object to str implicitly