(Solved) Working webmail before DNS change

After creating the email accounts with the domain name, you can access the email accounts before the DNS change by going to webmail.dreamhost.com and entering the full address as the username and the password.

I am moving a domain Dreamhost from another server.

Mail is currently managed on the existing server with a webmail app.

I would like to create the email accounts on Dreamhost before the DNS change takes place.

I already have a mirror set up for testing the webserver. However, when I try adding webmail to the mirror url I don’t reach the webmail app.

Is there a way to reach the Dreamhost webmail for the domain before the DNS change?

Thanks for any help on this.