Thanks for the info @zlaczo,
However, the new website works properly when using the IP address (22.214.171.124) or a fake domain (126.96.36.199.nip.io).
I just noticed that the application is redirecting all the requests to the IP address of the instance
$ curl -LI 188.8.131.52.nip.io
HTTP/1.1 302 Found
Date: Mon, 23 Nov 2020 08:32:16 GMT
Server: Apache/2.4.46 (Unix) OpenSSL/1.1.1d
Content-Type: text/html; charset=utf-8
That can be the issue with the load balancer. Can you configure the application with your domain and then point the load balancer to the new instance again?