New RFC connection SAPOSS as of 2020

Hi guys,

we are setting up a new connection to SAP Support Support in SAP S/4 HANA 1809 and need your help.

We have done steps as per the note 2740667 - RFC connection SAPOSS to SAP Service & Support backbone will change (latest) in January 2020 and the note 2738426 - Automated Configuration of new Support Backbone Communication.

In STC01 we executed the task list 'SAP_BASIS_CONFIG_OSS_COMM and the new connections SAP-SUPPORT_PORTAL and SAP-SUPPORT_PARCELBOX have been created with return code 200 OK.

While testing the connection SAP-SUPPORT_NOTE_DOWNLOAD in SM59 the following error appears:

"Direct connect to /H/<host>/S/3299/H/sapserv1a.wdf.sap.corp/S/3299/notesdownloads.sap.com:443 failed: NIECONN_REFUSED(-10)."

The tcp port 3299 is open in the firewall.

What can be the reason for this error?

Thank you for your advise.