I am building an application with Next.js that makes a websocket connection to a Node.js server running on AWS EC2. Since I am hosting the Next.js project on Vercel and am using one of the default domain names that it provides (*.vercel.app), it tries to make a secure websocket connection. For this purpose I need to use an SSL certificate with my Node.js server.
What I don't understand is what do I provide for the domain name which is required while generating an SSL certificate from Let's Encrypt.
Do I need to purchase a domain name specifically for my server?