How do I run a custom email from Splunk shell?

[t5as]

Hello,

I've built a custom email Python script to send as an alert in order to be able to add some CSS to my email.

I ran it using SMTP and it worked well once i entered the Windows CLI on my server and ran it from there.

However i tried to run it through Splunk custom command and experienced failure so i went to the Splunk shell CLI
on my server and tried to run it from there. From there, i got the following error: "SMTPServerDisconnected: Connection unexpectedly closed."

I need your help to figure out why this is happening since i've already been able to send normal emails from my Splunk.

Thanks in advance.