Go to Configuration > Click Domains > select the domain to edit
Copy the DNS Value listed.
Go to your Domain Host / DNS Provider and follow your provider’s instructions on adding a CNAME Record with the copied value from Tovuti. (The following screenshots are from GoDaddy, as this is a widely used DNS Provider)
Click "Add" in DNS Management. Choose CNAME as type, give this subdomain a name, and paste the value copied from Tovuti. Click Add Record.
If an A Record with the name used for the sub-domain already exists, it will need to be deleted and a new CNAME Record will need to be added with the value copied from Tovuti.
Important Note: Changing the DNS from an A Record to the CNAME Record can result in temporary downtime for this domain as it becomes active. Downtime will vary based on the Domain Host / DNS Provider and the TTL setting. For quicker Time To Live (TTL) set the TTL to 600 seconds (10 minutes). You should plan this transition during low traffic times to decrease interruption.