Hi
I have a problem with a virtual ubuntu 14.04 lts server I control via ssh login. I try to install Lets Encrypt certificate, which ends with this msg:

urn:acme:error:connection :: The server could not connect to the client to verify the domain :: Failed to connect to 217.170.205.92:443 for TLS-SNI-01 challenge

Port 443 obviously is not open. How to open it? It seems the answer is ufw, which I had to install, but when enabling it, I am warned that this might interfere with existing ssh connections, which is exactly what I use to communicate.

Now, what do I do then?

I propably don't fully understand the roles of apache, acme and what service or whatever shall listen to the certificate issue's testing.

https://help.ubuntu.com/community/UFW
should be something like
Restarting by addition to ufw rules usually issues a Warning.
Never had trouble with ssh when I saw it.

1 members found this post helpful.

In addition to opening the port for HTTPS, be sure the port for SSH is open before you enable UFW.

If SSH (22) is not already open, then you need to open it before turning on UFW.

Otherwise you will be locked out of SSH the moment you turn on UFW.

1 members found this post helpful.

There is also no reason to install ufw to "open" a port.
Unless you already have a firewall rule rejecting ir dropping such traffic, then the port is already "open"

More likely something using it already (webserver?), so stop that before running the LE client or maybe read the instructions.

Have you configured Apache to listen on port 443/HTTPS?

I found this ufw howto:
https://ubuntuforums.org/showthread.php?t=823741

Started with
Still my shell worked (aaahh!)
But port 80 blocked: no webpages served

then
webserver working!

Then installing the letsencrypt certificate.

Working! :-)

Thanx!

Ok. Port 80 (http) and port 22 (ssh) are working for you. You'll also need to open port 443 (https) to use your Let's Encrypt certificate.

1 members found this post helpful.

Have done. Works :-)