How to change the Site Name after a working server move?

I have a problem after moving the erp to a new server. After copying the full instance snapsh to a new Server with a new IP and ready Sub-Domain it is working and online. But sending emails with the old domain link in the bottom. So when i receive an email the Unsubscribe links goes to the www.oldsite.com/xyz… instead of the new subdomain > erp.newsite.com/xyz

I tried:
renaming the site in home>frappe>frappe bench>sites to the news domain erp.newsite.com which brings an error, also after server restart. like file not found site_config.json .
i tried: bench setup add-domain --site oldsite.com erp.newsite.com (for renaming the old site to the new domain but it says erp.newsite.com already exists. (but its not working with the newsite.com)

What files do i have to change and update, so erpnext is using the new sub-domain? Do i miss something?

If I were you
I will setup the new server based on the Easy Install found on bench/README.md at master · frappe/bench · GitHub

Delete the default site (please search for this command on forum)
Then upload the backup sql and the files to the server
Then create a new site (DNS multitenent on)
Point the A record to the new server IP
Then migrate site based on this database backup and unzip the public and private files.
Delete all email account and domain. Then reconfigure the email domain and mails

Please refer my previous post which contain a video about
ERPNEXT installation.

–sent from mobile–

thank @Riyas_Rawther you for your answer.

because of some customization’s i really hope there is also a way to update just the site domain-path without setting up all new. also because the instance is already up and running with the new sub domain just erpnext is taking the old domain for mail service. also when i use sendgrid, the beginning of the links point to the old domain.

any ideas?

I think you can do this just changing some of the text files in your new site in frappe bench ie currentsite.txt and rebuilding your bench setup via ‘bench setup’