In case you receive this error while running a transaction on the linked server, don't panic. This is caused by the RPC Endpoint Mapper service. Although this service is started by default on the Windows server, but still it may not work properly. Because of this, the App servers may not contact the database server. Though lot of solutions have been provided for removing this error on internet which works on Component Services Settings, but nothing works. So to remove this error, just reboot the server (linked). Its a simple fix, though you have to restart the server but it definitely works.