SOLVED!

After extensive troubleshooting, I found the issue: my computer name was "Belzebú" (with an accented ú).

I changed it to "Belcebu" (without the accent) and everything started working! The issue was how WildFly/Java handles special characters in system paths and hostnames.

I can't believe something as simple as an accented character could cause this, but here we are!

Lesson learned: Avoid special characters (á, é, í, ó, ú, ñ, etc.) in computer names when working with Java/WildFly.

Thanks to everyone who helped!