Domain validation using email is often regarded as the most basic and easiest validation option. There are a couple of options to get this step completed.
Alias Email Approval
The recommended method is to use one of the pre-approved alias email addresses listed below:
- Admin@yourdomain.com
- Administrator@yourdomain.com
- Webmaster@yourdomain.com
- Hostmaster@yourdomain.com
- Postmaster@yourdomain.com
*The email you are using can also be an alias on a sublevel if this sublevel is the name you would like to secure. Example: Admin@sublevel.yourdomain.com
Please Note: WHOIS registrant emails are no longer allowed for email-based domain validation. Please see here for more information.
An issue that we come across quite frequently is that the above email addresses do not exist for the organization/customer. A simple work around is to create an email forwarder that can be deactivated as soon as the validation has been completed.
Email to DNS TXT Contact
An additional option to use an existing email address would be to use the DNS to email option. Please create the following TXT record: _validation-contactemail.yourdomain.com. IN TXT the-email-you-would-like-to-use@any-domain.tld 
Note: Your DNS control panel may look different depending on your provider.
We understand that you might be wondering why you shouldn't use DNS validation in the first place. The regular DNS validation entry will change with each new order or reissue, but the email option will remain, and there are cases where email is preferred, making this option more useful.