What if the TestNG update site is genuinely unavailable? What are my alternatives?

If the TestNG site is down (check its status online), you'll need to wait until it's restored. As a temporary workaround, you can try downloading the TestNG JAR files directly from the official TestNG website (https://testng.org/doc/download.html) and adding them to your project's classpath manually. However, this won't provide automatic updates.