When using the hyperlink "Open in designer" in any portal pages, the Service Portal Page Editor is not loading, it remains blank.
Release or Environment
The issue is because the instance does not have a sp_portal with id=sp. In the UI action "Open in Designer", the portal name has been hardcoded as below:
window.open("$spd.do#/sp/editor/" + g_form.getValue('id') + "/", 'sp_config');
However, if the sp portal cannot be found, we will see "sys_id" of undefined console error.
Ensure the "sp" portal URL exists or modify the UI Action accordingly.