During secondary validation - DNS problem: networking error looking up A

Help
1

I know same topic is already posted and answered. Well, I don't find any solution for my problem so posting here.

Tried solving issue after reading this topic: During secondary validation - DNS problem: networking error looking up A but unfortunately didn't work.

Meanwhile I generated certificate using Wild Card solution. But afraid for renewal. It may stop generating certificate on renewal time.

My domain is: www.homeindiainfratech.com

I ran this command: certbot -d www.homeindiainfratech.com --nginx

It produced this output:

Obtaining a new certificate
Performing the following challenges:
http-01 challenge for www.homeindiainfratech.com
Waiting for verification...
Challenge failed for domain www.homeindiainfratech.com
http-01 challenge for www.homeindiainfratech.com
Cleaning up challenges
Some challenges have failed.

IMPORTANT NOTES:
 - The following errors were reported by the server:

   Domain: www.homeindiainfratech.com
   Type:   dns
   Detail: During secondary validation: DNS problem: networking error
   looking up A for www.homeindiainfratech.com

My web server is (include version): nginx/1.18.0 (Ubuntu)

nginx version: nginx/1.18.0 (Ubuntu)
built with OpenSSL 1.1.1  11 Sep 2018 (running with OpenSSL 1.1.1f  31 Mar 2020)
TLS SNI support enabled

The operating system my web server runs on is (include version): Ubuntu 20.04.1 LTS

Distributor ID: Ubuntu
Description:    Ubuntu 20.04.1 LTS
Release:        20.04
Codename:       focal

My hosting provider, if applicable, is: DigitalOcean

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

The version of my client is (e.g. output of certbot --version or certbot-auto --version if you're using Certbot): certbot 0.40.0

2

Hi @vinai

checking your domain via https://check-your-website.server-daten.de/?q=homeindiainfratech.com you use Digitalocean name servers.

Normally, these name servers are ok, not buggy.

-->> networking error looks like a temporary Letsencrypt problem -->> try it again.

PS: Currently your domain has only timeouts, so http validation will not work. But that's not your dns error.

3

Thank you @JuergenAuer

Yes, my server was down for a moment while upgrading.

Now it is fixed and certificate generated successfully.
The problem was NS propagation of my domain. To fix this I used Googl's DNS Flush "キャッシュをフラッシュする  |  Public DNS  |  Google for Developers". After that Lets Encrypt successfully generated certificate.

So, it was clearly not Lets encrypt problem