Fixing the MongoDB 'querySrv ECONNREFUSED' Nightmare on localhost

mongodb nodejs debugging
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There is a higher chance your code is fine if you are trying to connect to MongoDB Atlas and it keeps hitting you with querySrv ECONNREFUSED.

UPDATE (February 2, 2026): Root Cause Found! Since publishing this, it has been discovered that this error specifically affects Node.js v22+ on Windows, caused by Node not correctly using the system DNS resolver.

If you are on this specific stack, there is a one-line code fix discovered by the community (credit to this StackOverflow question):

js
require("node:dns/promises").setServers(["1.1.1.1", "8.8.8.8"]);

However, if you are on an older Node version, or prefer not to hardcode DNS servers in your application code, the solution below (manually constructing the Standard URI) remains the most robust way to bypass DNS issues entirely.

The problem

I encountered this error while trying to spin up my server and connect to my MongoDB database. The error is basically saying ‘your server is not failing to connect to the database; it’s failing to connect to the DNS system to ask where the database is’.

According to my research, this can be caused by DNS blocking, strict firewalls, or just a slow internet connection. Some blogs suggest whitelisting your IP address on MongoDB Atlas (I even tried whitelisting 0.0.0.0/0 out of desperation—please don’t do this)

After surfing the internet for hours, common suggestions includes:

  1. Switch to a Public DNS: change your DNS to Google (8.8.8.8) or Cloudflare (1.1.1.1).

  2. Flush your DNS: you can run this to clear your local DNS resolver cache.

    bash
    ipconfig /flushdns #run cmd as administrator before running

  3. Test to check if it has been resolved.

    bash
    ping _mongodb._tcp.test.egxt9uu.mongodb.net

If after this, it now resolves back to an IP Address — CONGRATS!

Other things you can try is probably reseting your router as it might also be an Internet Service Provider(ISP) Issue or Double checking your connection string.

Switching to the Standard URI

The most reliable fix I found is switching back to the Standard Connection String. This is the one starting with mongodb:// instead of mongodb+srv://.

The problem is, the +srv connection string is recommended because it automatically handles failover and service discovery. Finding the Standard URI requires a bit of technicality, as it appears to be completely hidden on the Atlas connection interface.

How to get the Standard URI

To construct the standard string, we need to find the actual server addresses hidden behind that short +srv URL. We can do this using the terminal.

When your server crashes, you are probably getting an error like this:

bash
Error: querySrv ECONNREFUSED _mongodb._tcp.test.egxt9uu.mongodb.net

That hostname in the error message is exactly what we need. We are going to perform an nslookup with the -SRV flag to ask the DNS server, “Where is the database actually located?”

Replace the hostname below with the one from your specific error message:

bash
nslookup -type=SRV _mongodb._tcp.test.egxt9uu.mongodb.net #(Replace the hostname with the one from your specific error message)

From the result we’ve literally gotten everything we need for our construction, everything the +srv string was hiding. This basically shows that there are 3 hidden servers and now we’ve gotten their real names (shard-00, 01, and 02), and their port (27017).

bash
svr hostname = ac-mvh7i5b-shard-00-00.egxt9uu.mongodb.net svr hostname = ac-mvh7i5b-shard-00-01.egxt9uu.mongodb.net svr hostname = ac-mvh7i5b-shard-00-02.egxt9uu.mongodb.net

The construction

With those details, we can piece the connection string together manually.

  • Protocol: Change mongodb+srv:// to mongodb://
  • Auth: Add your credentials (username:password@)
  • Host: List every server hostname we got from the nslookup, separated by commas, and add the port (:27017) to each one.
  • Database: Add the database name with a forward slash (e.g. /test).
  • Options: Append the standard options at the end.

The skeleton

text
mongodb://USER:PASS@HOST1:PORT,HOST2:PORT,HOST3:PORT/DB_NAME?OPTIONS

The final result

The final result will look something like this:

text
mongodb://<username>:<password>@ac-mvh7i5b-shard-00-00.egxt9uu.mongodb.net:27017,ac-mvh7i5b-shard-00-01.egxt9uu.mongodb.net:27017,ac-mvh7i5b-shard-00-02.egxt9uu.mongodb.net:27017/test?ssl=true&authSource=admin&retryWrites=true&w=majority

And voilà! You should be able to successfully connect to your database without the DNS headaches.🎉