Error getting Let's Encrypt certificate with IPV4

My domain is:

I ran this command: N/A.

It produced this output: N/A

My web server is (include version): Synology DS918+

The operating system my web server runs on is (include version): N/A

My hosting provider, if applicable, is: NameCheap.

I can login to a root shell on my machine (yes or no, or I don’t know): Yes if I enable SSH, but it is not currently enabled.

I’m using a control panel to manage my site (no, or provide the name and version of the control panel): I am using Disk Station Manager 6.2.2-24922 Update 4.

The version of my client is (e.g. output of certbot --version or certbot-auto --version if you’re using Certbot): N/A

My ISP doesn’t support ipv6, so I don’t have a AAAA record with my domain provider, just a CNAME record. I thought that this means Lets Encrypt would use ipv4, but when I try to generate a certificate, I receive the error “failed to connect to Let’s Encrypt. Please make sure the domain name is valid.”

1 Like

Hi @nickroyce

that’s not a problem. If you have only ipv4 and if ipv4 works, you can create a certificate.

But reading your check, ~~3 hours old -

Host T IP-Address is auth. ∑ Queries ∑ Timeout A yes 1 0
AAAA yes C yes 1 0

Salinas/California/United States (US) - Comcast Cable Communications

Your doesn’t have an ip address. That may (or may not) be a problem using Synology (I don’t know it). Perhaps add the same CNAME to your domain name.

Critical: Your server doesn’t answer, Grade T.

Domainname Http-Status redirect Sec. G -14 10.060 T
Timeout - The operation has timed out -14 10.037 T
Timeout - The operation has timed out -14 10.033 T
Timeout - The operation has timed out

So Letsencrypt can’t check your domain.

Firewall? Wrong router?


Allows your ISP incoming port 80 connections?


1 Like

Ok, so what I’m understanding from what you said is that I need to check if my ISP and router will allow incoming connections over port 80? And then I need to associate an A record IP address with the domain?

Your ISP allows traffic on port 80 and 443, but it seems like your router doesn’t…

Try to open port 80 and 443 from your router, then add your IP address as A record to your Namecheap control panel.

Thank you

1 Like

May be you don’t need an ip address with But I don’t know how Synology works. It may be a Synology limitation.

But first: Fix your router, so the www version is visible. The online tool must be able to check your port 80.

Then try it again only with the www version.

This topic was automatically closed 30 days after the last reply. New replies are no longer allowed.