If SmartPlant Foundation vaults exist on separate computers from the FTR Main Server, the FTR service is also installed on these computers so that files in these remote vaults are indexed locally; therefore, the FTR Main Server must know the location of these FTR servers for searching for remote collections.
Make sure that these remote vault hosts are selected in FTR Server configuration as Additional FTR Server Host in SmartPlant Foundation Desktop Client.