So when accessing http://your-new-ip you get the apache example page (something like this or this)
If yes, then what happens if you access http://your-new-ip/icingaweb2 ?
If no, what is the status of your webserver service (systemctl status apache2/httpd)
And also: please remember to give as much information as possible, meaning:
- OS distribution
- icinga/icingaweb versions (if relevant to the issue)
- modules installed (if relevant to the issue)
- screenshots
- config snippets (use markdown!)