Comment 2 for bug 1795955

Thanks for your report.

According to the stack trace, the Ubiquity crash is a consequence of the NM crash because the service disappeared from the bus.

Oct 3 18:38:06 ubuntu ubiquity[3468]: Exception in GTK frontend (invoking crash handler):
Oct 3 18:38:06 ubuntu ubiquity[3468]: Traceback (most recent call last):
Oct 3 18:38:06 ubuntu ubiquity[3468]: File "/usr/lib/ubiquity/plugins/ubi-wireless.py", line 190, in state_changed
Oct 3 18:38:06 ubuntu ubiquity[3468]: self.selection_changed(None)
Oct 3 18:38:06 ubuntu ubiquity[3468]: File "/usr/lib/ubiquity/plugins/ubi-wireless.py", line 121, in selection_changed
Oct 3 18:38:06 ubuntu ubiquity[3468]: self.nmwidget.is_row_connected()):
Oct 3 18:38:06 ubuntu ubiquity[3468]: File "/usr/lib/ubiquity/ubiquity/frontend/gtk_components/nmwidgets.py", line 348, in is_row_connected
Oct 3 18:38:06 ubuntu ubiquity[3468]: return self.view.is_row_connected()
Oct 3 18:38:06 ubuntu ubiquity[3468]: File "/usr/lib/ubiquity/ubiquity/frontend/gtk_components/nmwidgets.py", line 241, in is_row_connected
Oct 3 18:38:06 ubuntu ubiquity[3468]: if parent and self.wifi_model.is_connected(model[parent][0], ssid):
Oct 3 18:38:06 ubuntu ubiquity[3468]: File "/usr/lib/ubiquity/ubiquity/nm.py", line 148, in is_connected
Oct 3 18:38:06 ubuntu ubiquity[3468]: connectedap = get_prop(device_obj, NM_DEVICE_WIFI, 'ActiveAccessPoint')
Oct 3 18:38:06 ubuntu ubiquity[3468]: File "/usr/lib/ubiquity/ubiquity/nm.py", line 28, in get_prop
Oct 3 18:38:06 ubuntu ubiquity[3468]: return obj.Get(iface, prop, dbus_interface=dbus.PROPERTIES_IFACE)
Oct 3 18:38:06 ubuntu ubiquity[3468]: File "/usr/lib/python3/dist-packages/dbus/proxies.py", line 70, in __call__
Oct 3 18:38:06 ubuntu ubiquity[3468]: return self._proxy_method(*args, **keywords)
Oct 3 18:38:06 ubuntu ubiquity[3468]: File "/usr/lib/python3/dist-packages/dbus/proxies.py", line 145, in __call__
Oct 3 18:38:06 ubuntu ubiquity[3468]: **keywords)
Oct 3 18:38:06 ubuntu ubiquity[3468]: File "/usr/lib/python3/dist-packages/dbus/connection.py", line 651, in call_blocking
Oct 3 18:38:06 ubuntu ubiquity[3468]: message, timeout)
Oct 3 18:38:06 ubuntu ubiquity[3468]: dbus.exceptions.DBusException: org.freedesktop.DBus.Error.ServiceUnknown: The name :1.16 was not provided by any .service files

Did you report the n-m crash?