Message SAP XML_ADVICES001 - Error when sending the XML payment advice note for payment document &1 &2

Diagnosis
You attempted to send an XML payment advice note to a partner.

System Response
Sending the payment advice note electronically did not work, but thesystem still printed one.

Procedure for System Administration
Check whether the link to the system for SAP NetWeaver ProcessIntegration (SAP NetWeaver PI) is working.