Lead capture page not available

I'm back with the same issue but in the production environment!

What's the URL we have to use in the RSForm/Joomla tool :

• In the WebToLead of the Org it's 
  • <form action="https://webto.salesforce.com/servlet/servlet.WebToLead?encoding=UTF-8" method="POST">
• We tried <https://salussanguinis.my.salesforce.com/servlet/servlet.WebToLead>: not working but no error message?
• Or <https://https://salussanguinis.lightning.force.com/servlet/servlet.WebToLead>: idem

What's the URL to be used?

Thanks already for your support.

Very best

#Salesforce Developer