SMTP commands on 4D Server do not work

After turning to 4D server v17, sometimes I have problems with building and sending emails.
The problem already occurs executing the command:
SMTP_New( smtp_ID ) -> Function result
It return no errors, but smtp_ID=0.
This result a message is not build and it is not possible to send it.
For me it looks like the internet commands SMTP_… is not working on 4D server. The commands does not exist. Can this be right?

I found the solution in a French thread.
I copied the files in Contents/Plugins-folder from 4D to 4D Server.
Then it worked.