XF 2.0 Wrong links after migrating to new server

I have an issue with migration of my site forum.domain.com to a new VPS server. I copied all files from old VPS server to new VPS server and imported the database from mysqldump. It also had the exact NGINX configuration as the old one. So practically old server and new server are identical. However, when I updated the DNS server with the new IP address, all the links of the new site are wrong and now pointing to www.domain.com instead of forum.domain.com!

It's driving me crazy. In the ACP, I have correctly set the board and home url to forum.domain.com. I tried many options like removing all redirects so that only forum.domain.com will be valid. I have set all files permission correctly (read+write access allowed to data and internal_data directories). Still I get the same issue. When I switch back to the old site by changing the IP address in DNS server, links are working properly. Any ideas why this may be happening?
Hey Brogan thanks for dropping by. So was I doing the correct steps or did I miss anything? Which part of the database stores the base URL, maybe I need to edit that. Will try another attempt to migrate today.
Happy to report its working now. I've repeated the process from fresh start, requested new letsencrypt certificates and now site is working with correct links. Not sure what went wrong. I was using rclone to transfer the files over to new server. Probably I copied the wrong backup file.