Issue while Parsing XML data

If you are using store_xml => true then the xml filter does not care about random text prefixing the XML. However, the xpath option most certainly does. Try

    mutate { gsub => [ "message", "^[^<]+<", "<" ] }
    xml {
        source => "message"
        store_xml => false
        force_array => false
        remove_namespaces => true
        xpath => {
            "/FileTransferOperationRequest/fromUrl/text()" => "fromurl"
            "/FileTransferOperationRequest/toUrl/text()" => "tourl"
            "/FileTransferOperationRequest/filename/text()" => "filename"
        }
    }

which gets me

   "fromurl" => "/talendprojects/fileServices/workingFolder",
     "tourl" => "/mnt/gis/Input/NEMs/AvailabilityHuawei",
  "filename" => "pmresult_1526726662_15_201908271215_201908271230_201908271247.csv.gz",