johnwasser:
Does it work from a web browser when you use "http://address:81/"?
Yes, I'm using that one every day and it still works fine. I now downloaded (the outdated) version 23 of the Arduino ide and I get the same result: port 80 requests work, port 81 does not work. Then I tried a web service on port 8080 of the sam busy machine and also that one failed - that one requires a password so not too surprised it would fail but I did not get any response at all (not even asking for a password).
jhh