This likely to happen if you have configured multiple application servers in a standalone profile.
When you create the profile, all system applications including filetransferSecured are associated with the default server.
If you create additional server and use it mainly, you can associate switch the associated server to the new one by updating the following file.
profile_root/config/cells/cell_name/nodes/node_name/systemapps.xml
In this file, you see two points where the original server name is defined. Please replace them with the new server.
After recycling the new server, please see if you can export the app successfully.
#Support#SupportMigration#WebSphereApplicationServer(WAS)