The error message "app blocked by security settings" occurs when your operating system—whether Windows, macOS, or Android—prevents a program from running or installing because it cannot verify the app's safety. While this is a critical defense against malware, it often blocks legitimate niche software, older tools, or custom scripts.
Legacy Java applications often trigger this block if their security certificate is expired or they originate from an untrusted web domain. How to Fix the Block on Windows (10 & 11) app blocked by security settings