# SERVFAIL looking up A for **URL:** \ **Category:** Help\ **Created:** [December 9, 2021, 9:56pm UTC](https://community.letsencrypt.org/t/servfail-looking-up-a-for/167391 "2021-12-09T21:56:13Z")\ **Posts on this page:** 6\ **Page:** 1
**Author:** ![mikdale](https://avatars.discourse-cdn.com/v4/letter/m/7feea3/32.png) [@mikdale](https://community.letsencrypt.org/u/mikdale)\ **Post date:** [December 9, 2021, 9:56pm UTC](https://community.letsencrypt.org/t/servfail-looking-up-a-for/167391/1 "2021-12-09T21:56:13Z")
Please fill out the fields below so we can help you better. Note: you must provide your domain name to get help. Domain names for issued certificates are all made public in Certificate Transparency logs (e.g. [crt.sh | example.com](https://crt.sh/?q=example.com)), so withholding your domain name here does not increase secrecy, but only makes it harder for us to provide help. My domain is: [clemsonlca.org](http://clemsonlca.org) provided by Google Domains I ran this command: sudo certbot certonly --standalone -d [clemsonlca.org](http://clemsonlca.org) It produced this output: Certbot failed to authenticate some domains (authenticator: standalone). The Certificate Authority reported these problems: Domain: [clemsonlca.org](http://clemsonlca.org) Type: dns Detail: DNS problem: SERVFAIL looking up A for [clemsonlca.org](http://clemsonlca.org) - the domain's nameservers may be malfunctioning My web server is (include version): Apache/2.4.41 The operating system my web server runs on is (include version): Ubuntu 20.04.3 LTS My hosting provider, if applicable, is: N/A 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 1.22.0 When I check via [DNSSEC Analyzer - clemsonlca.org](https://dnssec-analyzer.verisignlabs.com/clemsonlca.org), I have all green lights... not sure what's going on. ---
**Author:** ![\_az](https://avatars.discourse-cdn.com/v4/letter/_/22d042/32.png) [@\_az](https://community.letsencrypt.org/u/_az)\ **Post date:** [December 9, 2021, 10:52pm UTC](https://community.letsencrypt.org/t/servfail-looking-up-a-for/167391/2 "2021-12-09T22:52:52Z")
I think it's probably due to you using private IP addresses: > **[Test result for clemsonlca.org: Fatal](https://letsdebug.net/clemsonlca.org/811487)** > > 2 unique issue(s) detected (ReservedAddress) Let's Encrypt have their DNS resolvers set up to strip private addresses from responses, which in turns breaks the DNSSEC signatures. Since your domain has DNSSEC enabled, that's where the SERVFAIL is coming from. You can't use private addresses for `--standalone` anyway. You will need to use a public IPv4/IPv6 address and port forward ports 80 and 443 to your server. ---
**Author:** ![rg305](https://sea3.discourse-cdn.com/letsencrypt/user_avatar/community.letsencrypt.org/rg305/32/91314_2.png) [@rg305](https://community.letsencrypt.org/u/rg305)\ **Post date:** [December 10, 2021, 2:23am UTC](https://community.letsencrypt.org/t/servfail-looking-up-a-for/167391/3 "2021-12-10T02:23:16Z")
OR You can use the `DNS-01` authentication method to obtain a cert - which won't need to reach your server. Of course, when you do get a cert, it won't be reachable via anyone on the Internet (without a VPN into your private network). So, you need to think this from that perspective... Where are the clients? How will the reach your service? ---
**Author:** ![schoen](https://sea3.discourse-cdn.com/letsencrypt/user_avatar/community.letsencrypt.org/schoen/32/79_2.png) [@schoen](https://community.letsencrypt.org/u/schoen)\ **Post date:** [December 10, 2021, 7:55am UTC](https://community.letsencrypt.org/t/servfail-looking-up-a-for/167391/4 "2021-12-10T07:55:50Z")
> [@\_az](#): > > Let's Encrypt have their DNS resolvers set up to strip private addresses from responses, which in turns breaks the DNSSEC signatures. Since your domain has DNSSEC enabled, that's where the SERVFAIL is coming from. Doesn't that behavior produce a rather less useful error message than people would see otherwise? (if we consider the underlying problem to be the private addresses listed in DNS) ---
**Author:** ![petercooperjr](https://sea3.discourse-cdn.com/letsencrypt/user_avatar/community.letsencrypt.org/petercooperjr/32/84698_2.png) [@petercooperjr](https://community.letsencrypt.org/u/petercooperjr)\ **Post date:** [December 10, 2021, 1:45pm UTC](https://community.letsencrypt.org/t/servfail-looking-up-a-for/167391/5 "2021-12-10T13:45:39Z")
> [@schoen](#): > > Doesn't that behavior produce a rather less useful error message than people would see otherwise? [Yes.](https://community.letsencrypt.org/t/no-valid-ip-addresses-found-for-host-with-ipv6-ula-and-gua-in-dns/165608) ---
**Author:** ![system](https://global.discourse-cdn.com/letsencrypt/original/3X/c/a/ca6c06ea1ea201324bba7048c6841ce60236468d.png) [@system](https://community.letsencrypt.org/u/system)\ **Post date:** [January 9, 2022, 1:46pm UTC](https://community.letsencrypt.org/t/servfail-looking-up-a-for/167391/6 "2022-01-09T13:46:12Z")
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