c# - RFID Locking user memory -

i working on rfid tags.i using speedway revolution reader(r-420) reading tags. http://www.impinj.com/speedway_revolution_uhf_rfid_reader.aspx using confidex steelware micro etsi monza tags (product no. 3000127) http://www.confidex.com/products-and-services/compare-uhf-products/524-confidex-steelwave-micro. using impinj's octane sdk. facing problem when trying lock user memory,i getting error.

this code using:

    static void main(string[] args)     {         try         {             // connect reader.             // change readerhostname constant in solutionconstants.cs              // ip address or hostname of reader.             reader.connect(solutionconstants.readerhostname);              // assign tagopcomplete event handler.             // specifies method call             // when tag operations complete.             reader.tagopcomplete += ontagopcomplete;              // configure reader default settings.             reader.applydefaultsettings();              // create tag operation sequence.             // can add multiple read, write, lock, kill , qt             // operations sequence.             tagopsequence seq = new tagopsequence();               // define tag write operation sets access password.              tagwriteop writeop = new tagwriteop();             // assumes current access password not set             // (zero default)             writeop.accesspassword = null;             // access password in reserved memory bank.             writeop.memorybank = memorybank.reserved;             // pointer start of access password.             writeop.wordpointer = wordpointers.accesspassword;             // new access password write.             writeop.data = tagdata.fromhexstring("11112222");              // add tag write op tag operation sequence.             seq.ops.add(writeop);              // create tag lock operation lock              // access password , user memory.             taglockop lockop = new taglockop();             lockop.accesspasswordlocktype = taglockstate.lock;             lockop.epclocktype = taglockstate.lock;               // add tag lock op tag operation sequence.             seq.ops.add(lockop);              // add tag operation sequence reader.             // reader supports multiple sequences.             reader.addopsequence(seq);              // start reader             reader.start();         }         catch (octanesdkexception e)         {             // handle octane sdk errors.             console.writeline("octane sdk exception: {0}", e.message);         }         catch (exception e)         {             // handle other .net errors.             console.writeline("exception : {0}", e.message);         }          // wait user press enter.         console.writeline("press enter exit.");         console.readline();          // stop reading.         reader.stop();          // disconnect reader.         reader.disconnect();     }      // event handler called when tag      // operations have been executed reader.     static void ontagopcomplete(impinjreader reader, tagopreport report)     {         // loop through completed tag operations         foreach (tagopresult result in report)         {             if (result tagwriteopresult)             {                 // these results of settings access password.                 // cast correct type.                 tagwriteopresult writeresult = result tagwriteopresult;                 // print out results.                 console.writeline("set access password complete.");                 console.writeline("epc : {0}", writeresult.tag.epc);                 console.writeline("status : {0}", writeresult.result);                 console.writeline("number of words written : {0}", writeresult.numwordswritten);             }             else if (result taglockopresult)             {                 // cast correct type.                 // these results of locking access password or user memory.                 taglockopresult lockresult = result taglockopresult;                 // print out results.                 console.writeline("lock operation complete.");                 console.writeline("epc : {0}", lockresult.tag.epc);                 console.writeline("status : {0}", lockresult.result);             }         }     } } 

}

this error getting : "no response tag"

have followed guide? http://learn.impinj.com/articles/en_us/rfid/locking-memory-on-epc-rfid-tags/