MongooseServerSelectionError: connect ECONNREFUSED 127.0.0.1:27017
The MongoDB driver couldn’t find a reachable server for the connection string.
Exact message you may see
MongooseServerSelectionError: connect ECONNREFUSEDServer selection timed out
Seen on:
Node.js
Meaning
Local mongod not running, Atlas IP access list blocking you, DNS SRV failures (mongodb+srv), TLS problems, or localhost resolving to IPv6.
Common causes
- mongod not running locally
- Atlas Network Access not including your IP
- mongodb+srv DNS lookup failing
- localhost → ::1 while mongod listens on IPv4
⚡ Quick fix
- Start MongoDB / check the Atlas cluster
- Add your IP in Atlas
- Use 127.0.0.1 instead of localhost
- Test with mongosh using the same URI
Detailed fix by platform
Node.js
mongoose.connect('mongodb://127.0.0.1:27017/app')
How to diagnose
- Reason — The nested reason (ECONNREFUSED, ETIMEOUT, ENOTFOUND)
- Access — IP allowed?
🔧 Still not fixed?
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Where this error sits
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Last updated 13 Oct 2026