I cannot get the PUT method to work. What is wrong with my Google Script code ?

I cannot get the PUT method to work. It does not error but it also does not update the sheet. The same code framework will add columns (with a POST), and pull back data (with a GET)..but it will not put data into the sheet.

Tried it with Content-Type in the Headers section and Options, with out single quotes and with,..all kinf\ds of variations but no good.

var headers3 = {            "Authorization" : "Bearer " + basicToken,                                  };
var url3 = 'https://api.smartsheet.com/2.0/sheets/' + googleSheetData1[x][0]+ '/rows' ; 

var options3 = {
   'method': "PUT", 

   'content-type':'application/json', 

    'headers': headers3,

    'muteHttpExceptions' : true, 

    'payload': JSON.stringify([{"id":rowidx,"cells":[{"columnid":colidx,"value":"kevintest"}]}])   

      }    

try{              var response3 = UrlFetchApp.fetch(encodeURI(url3),options3);