retrieving and rendering messages from sessionStorage from a form

If someone could help me with this I would be eternally grateful! In a course I’m taking my lecturer wrote the below code for submitting data from a form when the submit button is pressed. It stores this to sessionStorage and then renders the received messages below the form. I made sure to copy it exactly and mine doesn’t work. It seems to be because the .fullName, .emaill, .feedbackType and .comment are not being assigned a type. When I ran the lecturers code file from my vscode and checked it in the browser his worked fine. My work is identical to his bar some different CSS styles.

`function submitMessage(event) {
 event.preventDefault();
 const email = document.getElementById('email').value;
 const fullName = document.getElementById('fullName').value;
 const feedbackType = document.getElementById('feedbackType').value;
 const comment = document.getElementById('comment').value;
 const messageObject = {
   email,
   fullName,
   feedbackType,
   comment,
 };

 let currentMessages = [];

 if (window.sessionStorage.getItem('messages')) {
   currentMessages = JSON.parse(
     window.sessionStorage.getItem('messages')
   );
 }

 currentMessages.push({ messageObject });
 /*temporary fix, find a solution for this error, .push not working/recognised. Code matching lectures is currentMessages.push(messageObject)*/

 window.sessionStorage.setItem(
   'messages',
   JSON.stringify(currentMessages)
 );
 JSON.parse(window.sessionStorage.getItem('messages'));
 renderMessages();
}
function renderMessages() {
     let currentMessages = [];

     if (window.sessionStorage.getItem("messages")) {
         currentMessages = 
             JSON.parse(
                 window.sessionStorage.getItem("messages")
             );
     }

     let listItems = [];
     for (let i = 0; i < currentMessages.length; i++) {
         let listItem = " ";
         const currentMessage = currentMessages[i];
         listItem += `<dt>${currentMessage.fullName} - ${currentMessage.email}</dt>`;
         listItem += `<dd>${currentMessage.feedbackType}: ${currentMessage.comment}</dd>`;
         listItem += `<br />`;
         listItems.push(listItem);
     }
     let descList = document.getElementById('currentMessages');
     descList.innerHTML = listItems.join('');
 }

 renderMessages();`