New Relic Agent Connection Error Fix

In this tutorial, you'll learn about New Relic Agent Connection Error Fix. We cover key concepts, practical examples, and best practices.

Your New Relic agent logs Failed to connect to collector — the agent cannot reach New Relic's ingestion endpoint. The license key is wrong, the collector endpoint is misconfigured, or a firewall blocks outbound traffic.

The Problem

New Relic Agent: Failed to connect to collector.newrelic.com:443
Reason: connection refused

The application server cannot reach collector.newrelic.com on port 443. Corporate firewall rules, VPC configurations, or DNS resolution failures prevent the outbound connection.

Step-by-Step Fix

1. Verify the license key

# Check the license key in the agent config
grep license_key /etc/newrelic/newrelic.cfg

# Ensure it's 40 characters long
echo -n "your_license_key_here" | wc -c

2. Test network connectivity

# Test connection to New Relic collector
nc -zv collector.newrelic.com 443

# Test alternate endpoint
nc -zv collector.eu.newrelic.com 443

# Test with curl
curl -v https://collector.newrelic.com/status

# For EU region
curl -v https://collector.eu.newrelic.com/status

3. Configure the correct endpoint

# newrelic.ini (PHP)
newrelic.license = "your_license_key"
newrelic.appname = "My Application"
newrelic.daemon.collector = "collector.newrelic.com"

# For EU region
newrelic.daemon.collector = "collector.eu.newrelic.com"

4. Configure proxy settings

# Via environment variable
export NRIA_PROXY=http://proxy.company.com:8080

# In agent config
newrelic.daemon.proxy = "http://proxy.company.com:8080"

5. Enable debug logging

newrelic.daemon.loglevel = "debug"
newrelic.daemon.logfile = "/var/log/newrelic/newrelic-daemon.log"

tail -f /var/log/newrelic/newrelic-daemon.log

6. Restart the agent

sudo systemctl restart newrelic-daemon
sudo systemctl restart php-fpm  # or your app server

Expected output:

New Relic Daemon Connection:
  Collector: collector.newrelic.com:443
  Status: Connected
  License Key: ****abc123 (valid)
  Applications: My Application (reporting)

Prevention Tips

• Verify network access to New Relic endpoints during infrastructure setup
• Use environment-specific license keys (staging vs production)
• Configure proxy settings if behind a corporate firewall
• Monitor agent status in New Relic's Agent Status dashboard
• Test collector connectivity during deployment pipelines

Common Mistakes with connection error

1. Overlapping type class instances that cause GHC to reject the program with ambiguous dispatch errors
2. Non-exhaustive pattern matches that compile with warnings then crash at runtime
3. Misunderstanding that String is [Char] with poor performance for large text operations

These mistakes appear frequently in real-world NEWRELIC code. DodaTech's contributors have identified these patterns through analysis of open-source projects and production systems.

Practice Exercise

Write a pure function that safely divides two integers using Maybe, then test it with edge cases like division by zero and negative numbers.

This exercise reinforces the concepts covered in this guide. Try implementing it before checking online solutions.

FAQ