Called MAIL FROM without being connected

[ELMIT]

I know that this was asked many times, but I cannot find any solution for that yet.

I have parallel installed SmartSerialMail on a Windows machine and that works fine. So it must be a setting within phplist and not as I thought before at the remote smtp host.

SmartSerialMail tested the outgoin server options and set it to:
Port: 587
Security: None

I tried within PHPlist port 25 and port 587, but the Error remains. What should it mean anyway?