Request Failed. Specified Argument was out of Range, Parameter Name: Index undefined

Question

I have this custom action in sharepoint where the page will be redirected to another url but the components of the URL are dependent on a fielvalue in its parent folder, Request Failed. Specified Argument was out of Range, Parameter Name: Index undefined keeps popping up every time i press the button for the first time, but after that the code runs smoothly

here is the part of my code where the error occurs

                        function getParentFolder() {
                            console.log('getParentFolder')
                            var defer = $.Deferred();
                            var urlParams = new URLSearchParams(window.location.search);
                            var myParam = urlParams.get('RootFolder');
                            //var context = SP.ClientContext.get_current();
                            var web = context.get_web();
                            var folder = web.getFolderByServerRelativeUrl(myParam);
                            context.load(folder);
                            context.executeQueryAsync(function (data) {
                                defer.resolve(folder);
                                // onFolderSucceeded(folder)
                        }, function(sender, args){
                            defer.reject(sender, args);
                        })
                        return defer.promise();
                        };

its goes to defer.reject every time i press button for the first time