Solved errors
Direct solutions to common programming errors and system issues.
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Fix SSH 'Connection Refused' Error — All Causes (2026)
Fix "ssh: connect to host port 22: Connection refused". All causes: SSH not running, wrong port, firewall, fail2ban ban. Diagnostic flow with nc and nmap.
Fix SSH 'Host Key Verification Failed' Error (2026)
Fix "WARNING: REMOTE HOST IDENTIFICATION HAS CHANGED! Host key verification failed." Safe steps: ssh-keygen -R, known_hosts edit, StrictHostKeyChecking options explained.
compile: version does not match go tool version — Fix in 60 Seconds
Fix "compile: version does not match go tool version" in Go. Caused by GOROOT mismatch, stale PATH, or multiple Go installs. Copy-paste fix for Linux, macOS, and Windows.
db2stop force: How to Stop a DB2 Instance Safely (2026 Guide)
Learn how to use db2stop and db2stop force to stop a DB2 instance safely. Includes error handling when db2stop force fails.
Fix: React Modal App Element Not Defined [react-modal Setup Guide]
Fix "Warning: react-modal: App element is not defined" error. Learn Modal.setAppElement() for CRA, Next.js, Vite, and testing.
Mac OSX: OSError: MoviePy Error missing magick font
If you are trying to render font using moviepy you will need to install ghost script with brew install Ghostscript to have all the required fonts by moviepy. Check here for full details.
SAP Error M7053: Posting Only Possible in Periods
The error is common when *Actual GI date* was not given by the user, in this case, SAP will use the current system date. Usually, the current system date is not in the valid period and the error *M7053* is raised. Check the full solution to know how...
SOLVED: ImportError: No module named Cython.Build
When you try to install a python package and you get the error
Regex for validate two letter country
Here we provide a long regex to validate ISO 3166-1 alpha-2 two letter country codes.
OSX MAC Solution to SSH Broken Pipe
In this article, we explain how to avoid the "Broken Pipe" error. You will need to edit you sh config file /etc/ssh/ssh_config or ~/.ssh/config and set the ServerAliveInterval to 120 and TCPKeepAlive to no for all hosts. Check here for the complete information.