Troubleshooting Archives

Zabbix Database Error: No such file or directory After unattended-upgrade

Makson Lee / June 14, 2026

After unattended-upgrade automatically ran on one of my Zabbix servers, the Zabbix frontend started showing a confusing database error. When […]

After upgrading one of my Jenkins servers from Ubuntu 24.04 to Ubuntu 26.04, I noticed that the Built-In Node was

I installed WireGuard on an Ubuntu 26.04 EC2 instance and connected to the instance through an AWS SSM Session Manager

When I connected to an Ubuntu 24.04 server using PuTTY, I could open vi, enter insert mode, and paste text

Makson Lee / April 29, 2026

After running Kubernetes for a while, I noticed that some systems running inside my Kubernetes cluster started reporting low disk

Makson Lee / April 27, 2026

In my previous post, I used EJBCA RA Web to issue ThingsBoard device certificates from an externally signed IoT device

Makson Lee / February 21, 2026

This post explains a common (and confusing) failure mode when running EJBCA on WildFly with MariaDB/MySQL: An exception has occurred.JDBC

Makson Lee / February 5, 2026

When Jenkins is authenticated by Keycloak (OIDC) and sits behind NGINX, “session timeout” is not a single knob. You can

Makson Lee / February 3, 2026

WordPress email delivery can be unreliable when it uses PHP mail (password resets, contact form notifications, admin alerts). The fix

Makson Lee / January 26, 2026

This guide enables ACME v2 on an existing Smallstep Step CA deployment, then shows how a host like test.maksonlee.com can