MongoDB Troubleshooting Guides

MongoDB errors can surface at the worst possible moments — during deployments, under peak traffic, or in the middle of critical operations. This collection of 4 troubleshooting guides covers the most common MongoDB issues encountered in database management, queries, and data operations. Each article walks through specific error messages with step-by-step diagnosis, root cause analysis, and verified solutions. Whether you're dealing with configuration problems, authentication failures, timeout errors, or unexpected behavior, these guides are designed to get you from error message to resolution as quickly as possible. Solutions are backed by official documentation and real-world production experience.

Error Quick Reference

Article	Description
Fixing 'MongoDB Connection Refused' and Related Network Errors: A Complete SRE Guide	Resolve MongoDB connection refused, timeout, and authentication failed errors. SRE guide to diagnosing bind_ip, firewalls, disk space, and crash recovery.
MongoDB 'connection refused' Error: Complete Troubleshooting Guide	Fix MongoDB connection refused, authentication failed, timeout, and too many connections errors. Step-by-step diagnostic commands with root cause analysis.
MongoDB Replication Lag: How to Check, Monitor, and Fix Secondary Delay	Learn how to accurately check MongoDB replication lag using rs.status() and rs.printSecondaryReplicationInfo(), monitor delay, and resolve common performance bo
Troubleshooting MongoDB Connection Pool Exhaustion and Timeout Errors	Fix MongoDB connection timeouts, "server selection timed out", and pool exhaustion errors. Learn how to configure maxPoolSize, socket timeouts, and debug limits