Can't connect to port 443 on Windows Server 2022

My domain is:

I ran this command: telnet 443

It produced this output: Connecting To not open connection to the host, on port 443: Connect failed

My web server is (include version): IIS 10.0.20348

The operating system my web server runs on is (include version): Windows Server 2022 21H2

My hosting provider, if applicable, is: AWS LightSail

I can login to a root shell on my machine (yes or no, or I don't know): yes

I'm using a control panel to manage my site (no, or provide the name and version of the control panel): no

I installed a brand new Windows Server, I added my domain and created this binding. 443 appears to be enabled in my firewall as shown here Telnet doesn't seem to access the 443 port as shown here.

What else should I be looking at ?

Nothing you wrote has anything to do with Let's Encrypt certificates.

You should have better results asking that question in a forum that focuses on IIS.

You may also want to trade in telnet for more suitable tools such as curl or openssl s_client.


Hello @Corobori,

What make you believe that?

You very likely have one or more of the firewalls between your site server and the Internet filtering Port 443.

$ nmap -Pn -p80,443
Starting Nmap 7.80 ( ) at 2024-01-17 00:09 UTC
Nmap scan report for (
Host is up (0.081s latency).
rDNS record for

80/tcp  open     http
443/tcp filtered https

Nmap done: 1 IP address (1 host up) scanned in 2.00 seconds


Here is a list of issued certificates |, the latest being 2024-01-16.


This might help or an AWS forum



You need to open TCP port 80 and TCP port 443 in Windows Firewall but you also need to add HTTP (TCP port 80) and HTTPS (TCP port 443) in the lightsail web administration console..


Indeed this issue didn't have anything to do with Let's Encrypt but with my lack of knowledge of AWS.

Adding the 443 port under Networking in Lightsail fixed the issue.


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