Show you how to us XMLRPC APIs via the generic HTTP-Request-node, by the example of posting to a wordpress blog
This is also a feasible workaround if a specific n8n integration does not work or stops working (which happens e.g. with the Wordpress node)
How it works
First, the XML payload for the request is being prepared (in a code node, which also properly escapes special character in the values that you want to send to the XMLRPC endpoint)
Then, the HTTP Request node sends the request using the HTTP post method
Last, the returned XML response is converted to JSON which a conditional node uses to determine whether th operation was successful or not
Setup steps:
Import workflow
Ensure you have a wordpress blog with a user that has an app-Password
Edit the "Settings"-node and enter your individual values for url/user/app-pw