Is there anyone to help me to process Email Capture Plug-in? I created script and implementation, and I sent email which is listed in manage plug-in implementation. I tried to send email but I got 554 Relay access   denied: invalid request type [5940170_SB1] for RCPT TO email address.

Might just be because you can’t email out from a sandbox. Do a test on prod with the same code

@PNJ email plugin is for inbound not outbound and works just fine in Sandbox unless you're actually trying to send an email from the plugin itself 😉 . @Borys Peten did you resolve this?

No.