Failed to load term set group for visitors and members in sharepoint2013

Question

I have created the term group and term set in SharePoint 2013.i have loaded the term set retrieve query after loading the files are sp.js, sp.taxonomy.js, sp.publishing.js.The termset retrieve function is javascript code. its works fine for admin users.but it's throwing an error for visitors and member users.

error is

Cannot invoke method or retrieve property from nul…nt.Taxonomy.TaxonomySession.GetTaxonomySession

I have used the below code

  var ctx = SP.ClientContext.get_current();
    var taxonomySession = SP.Taxonomy.TaxonomySession.getTaxonomySession(ctx);
    var termStore = taxonomySession.getDefaultSiteCollectionTermStore(); 
    var termsList = [];
    var termSet = termStore.getTermSet("5f9b30c9-6beb-45cb-bfeb-3a1fdc49159a");
    var terms = termSet.get_terms();
    ctx.load(terms);
    ctx.executeQueryAsync(
        function () {
           var navTerms = [];
           var temp1 = 0;

           var termEnumerator = terms.getEnumerator();
            while (termEnumerator.moveNext()) 
            {
                var parentTerm = termEnumerator.get_current();                              
                navTerms.push(parentTerm.get_terms());
                ctx.load(navTerms[temp1]);
                temp1++;
             }
            ctx.executeQueryAsync(function () {
               for (var j = 0; j < navTerms.length; j++) {
                   var terms = [];
                   for (var i = 0; i < navTerms[j].get_count() ; i++) {
                       var navTerm = navTerms[j].getItemAtIndex(i);
                       terms.push({ termName: navTerm.get_name(), TargetURL: navTerm.get_localCustomProperties()._Sys_Nav_SimpleLinkUrl });
                   }
                   if (terms.length > 0) {
                       termsList.push({ id: j, termSetName: navTerms[j].getItemAtIndex(0).get_pathOfTerm().split(";")[0], terms: terms })
                   }
               }

            }, function (sender, args) {
               console.log('Request failed ', sender, args);
            });   
        }, function (sender, args) {
            //failure loading groups
            console.log('failure loading groups ', sender, args);
        });

suggest any idea to resolve this issue for read permission users.