If you are trying to access your W-2 online, you can contact your company's payroll department to help you. If that is unsuccessful, you can request they mail a paper copy to your new address. The IRS will also assist you, you can contact the IRS Taxpayer Assistance Center here: Taxpayer Assistance Center Office Locator
Here is an article with more information: What To Do If You Haven't Received a W-2
You can file an extension for 2024: Free Federal Extension