Could be I have the same problem. Which setting did you change ?

It is not very likely that you will have exactly the same problem: I had the
problem on my notebook, which I use in two different network environments.
Since I am not using DHCP, I need to manually enter the DNS Server adresses.
I forgot to enter one of the server adresses, and as a result of that the
seti server adress could not be resolved.
So I think I had a very specific issue because I had messed around with my
network settings.

On the other hand, it is very well possible that you have a problem with
either your network setting (if you use a lan to connect to the internet),
or with your dial in settings (if you have a dial up connection). Just try
to remenber wether you changed something recently.

Regards
Wolfgang