I have applied that patch. Same problem.
Windows 2012 R2. Server running well. No problems with anything else.

Same error is shown in command line when running command also:

letsencrypt.exe –plugin iissite –siteid 134 –emailaddress myaddress@example.com –accepttos –closeonfinish

Error:

Hello,

Few the domain your using is it actually resolving through the internet?

As it has to autorize through http (so the url needs to lookup from LE's servers)

in your case www.letsencrypttest2.com which i can already tell you doesn't resolve properly.

Make sure you use LE certs only with valid IIS Bindings else it will fail.

Regards,

Marco

I have just tried with a valid domain that resolves.
Set its port 80 bindings to All Unassigned as well.
Still fails with same error.
Any other ideas?

If you get the same error with a valid domain (and all IIS bindings resolve in that site) i would recommend contacting the Lets Encrypt win Simple client dev's.

Do note if a single binding does not resolve proper you will get an error with LetsEncrypt.

They had a similar issue logged here:

https://github.com/Lone-Coder/letsencrypt-win-simple/issues/648

But it was since closed, (and the version trevor given earlier in this topic is after the version they asked the guy who reported the bug to check).