I use Ubuntu 16.04 with Bash, Nginx, and Certbot and I ran the command certbot --nginx -d "$domain" -d www."$domain" but this Certbot operation failed due to a misconfigured A DNS record (an issue which is now fixed in the DNS management tool (DNSMT) of the hosting provider).
I wonder how should I proceed after the execution failure due to the wrong A record and after fixing it in the DNSMT.
Should I just re-run the above command? Or should I first run certbot --nginx rollback, that, if I understand correct, will rollback any change already made by Certbot (this is the only change I did with Certbot since installing the operating system) and only then re-running the above command?
Since it was unable to get a certificate, Certbot automatically reverted the temporary changes it made to the configuration, and didn’t make any permanent changes. There should be nothing to roll back.
You can run certbot --nginx -d "$domain" -d www."$domain" again now.
Since validation failed due to a DNS issue that was separate from Certbot and Nginx, there’s no reason to think there’s anything wrong with the Nginx configuration. (If there is, that’s a bug!)