WiFi problem, loss of DHCP/DNS when changing from one SSID to another but OK from turn on

[Chris Green]

I am having a problem with WiFi connections from my Lenovo laptop
running xubuntu 17.10.

I have a number of different WiFi sources round our rather rambling
house so the laptop has to move from one to another as I move around.

When moving to one SSID in particular it always fails to get proper
settings via DHCP, in fact it acts rather as if DHCP fails altogether.
Network Manager tells me I'm connected but the WiFi has no IP address
and thus, obviously, no functional connection.

If I turn the laptop off and power it up then it connects OK to the
same SSID.  If I just reset the laptop it *doesn't* connect
successfully.  Connecting to other SSIDs around the house doesn't seem
to suffer from the same problem, it's just one SSID where this
happens. (I'm pretty sure this is the case but I've not spent a very
long time checking).

I've found that if I do "nmcli off" followed by "nmcli on" (as root of
course) then I get a good connection again.  Disconnecting and
reconnecting from the Network Manager applet in the panel doesn't
clear the problem though.

Does anyone have any suggestions as to what might be wrong?

-- 
Chris Green