@Marcos-silva, I just tested the Alexa TRIGGERcmd Smart Home skill myself and it worked for me. Have you tried using it without your Alexa Routine? Like just, "Alexa, turn on calculator" ? One theory I have is maybe you changed something about your command, which would delete and re-create the Alexa device. If so, you'd have to re-add it to your Routine.

@Marcos-silva, please confirm, if you use the website, it's working fine, it just Alexa that doesn't work? Also, not even the built-in calculator and notepad commands are working with Alexa? You could try the "turn monitors on" powershell command here, but success it depends on your hardware I think. It didn't work for me for example, even though turn monitors off powershell command did work. You'll see that the script that effectively presses the Print Scrn button did work to turn my monitor back on.