quarkusio/quarkus · error · MongoConfigurationException

Unable to look up TXT record for host

Error message

Unable to look up TXT record for host 

What it means

Alongside SRV records, mongodb+srv:// discovery fetches TXT records for connection options. resolveTxtRequest wraps the Vert.x TXT lookup in a catch-all and converts any failure (timeout, resolver error) into MongoConfigurationException with this message.

Source

Thrown at extensions/mongodb-client/runtime/src/main/java/io/quarkus/mongodb/runtime/dns/MongoDnsClient.java:189

            Duration timeout = mongoConfig.dnsLookupTimeout();
            return Uni.createFrom().<List<String>> deferred(
                    new Supplier<>() {
                        @Override
                        public Uni<? extends List<String>> get() {
                            return dnsClient.resolveTXT(host);
                        }
                    })
                    .onFailure().retry().withBackOff(Duration.ofSeconds(1)).atMost(3)
                    .invoke(new Consumer<>() {
                        @Override
                        public void accept(List<String> strings) {
                            log.debugf("Resolved TXT records for %s: %s", host, strings);
                            TXT_CACHE.put(host, strings);
                        }
                    })
                    .await().atMost(timeout);
        } catch (Throwable e) {
            throw new MongoConfigurationException("Unable to look up TXT record for host " + host, e);
        }
    }
}

View on GitHub (pinned to e1c734241f)

Solutions

1. Inspect the wrapped cause to identify timeout vs. resolver refusal
2. Repair DNS resolution in the deployment environment (check /etc/resolv.conf, CoreDNS, VPN)
3. Run `nslookup -type=TXT <host>` from the same network to reproduce and verify
4. If DNS is unreliable, specify all options explicitly in the connection string/hosts so TXT discovery isn't needed

Example fix

// before (relies on TXT discovery in a DNS-restricted network)
quarkus.mongodb.connection-string=mongodb+srv://cluster0.abc123.mongodb.net/db
// after (explicit options)
quarkus.mongodb.connection-string=mongodb+srv://cluster0.abc123.mongodb.net/db?ssl=true&replicaSet=rs0
quarkus.mongodb.hosts=shard-0.abc123.mongodb.net:27017

// Verify TXT records resolvable before building client
try {
    javax.naming.directory.DirContext ctx = new javax.naming.InitialDirContext();
    javax.naming.directory.Attributes attrs = ctx.getAttributes("dns:/" + srvHost,
        new String[]{"TXT"});
    if (attrs.get("TXT") == null) {
        log.warn("No TXT records for " + srvHost + "; specify connection options explicitly");
    }
} catch (Exception e) {
    throw new ConfigurationException("TXT lookup for " + srvHost + " failed: " + e.getMessage(), e);
}

try {
    return mongoClients.create(name);
} catch (MongoConfigurationException e) {
    if (e.getMessage().contains("TXT record")) {
        // fall back to explicit options instead of TXT discovery
        throw new IllegalStateException("Specify ssl/replicaSet options explicitly; TXT lookup failed", e);
    }
    throw e;
}

When it happens

Trigger: resolveTxtRequest(host) calls the Vert.x resolver for the host's TXT records and the lookup throws or exceeds the `.atMost(timeout)` deadline.

Common situations: Same DNS infrastructure problems as SRV lookups (blocked port 53, pod DNS misconfig); Atlas TXT records unreachable due to split-horizon DNS; transient resolver failures during application startup.

Related errors

• No SRV records available for host
• Unable to look up SRV record for host
• Unable to resolve "${value}"
• Unknown DNS record type:
• Failed to parse CIDR address "${value}"

AI-assisted analysis of quarkusio/quarkus@e1c734241f (2026-09-05). Data as JSON: /api/errors/bf380c8079999137. Report an issue: GitHub.