External monitor not working properly

Hello, sorry if I'm so late but I was looking for external monitor articles today and I bumped into this.

From my experience, the most common error when scripting external monitors is to have some exceptions or some other string that populates the output file. 

The easiest way for me to debug this, is to manually run the monitor instance.

Every edit you make to the script in the "System > File Management > External Monitor Program File List" in the GUI is reflected in a file that's stored in /config/filestore/files_d/Common_d/external_monitor_d/ directory, which has the same name of your script and also append some "versioning" to it, ex. :Common:sample_monitor_VERSIONNUMBER 

To run it manually you need to specify every parameter that you're passing in the script, the default is <server IP> <L4 port> <timeout> 
example: 

./\:Common\:sample_monitor_123456_1 10.0.0.1 80 16 

Doing so, you can easily see if there's syntax errors or anything when running the monitor, and what changes when you change the string. 
You should expect NO OUTPUT when you want the script to mark an object down.