To access Webmail before adjusting your DNS, you can use the URL:
https://10.0.0.1:2096
(replace 10.0.0.1 with your server's public IP)
You would use your full email address as the username and your account's password to log in.
Alternatively, you can log in to cPanel using the URL
https://10.0.0.1:2083
(replace 10.0.0.1 with your server's public IP)
You would use your cPanel username and password to login then
cPanel -> Email -> Email Accounts next to the account you want to login to "Check Webmail."
Additional information in our documentation here: