After following online doc https://ftpdocs.broadcom.com/cadocs/0/CA%20Identity%20Manager%20r12%205%20SP3-ENU/Bookshelf_Files/HTML/Import_SelectBoxData_XMLFile.html
to import the XML file, it simply disappears without any indication in the server logs
Identity Manager 14.4
This is due to the proxy server policy blocking the import
Modify proxy rules to unblock the import function