Below you can find a table of the results received within the CORE service.
CORE Main Response Codes
CORE Additional Status Codes
Safe to send
Domain is Inexistent
The Domain of the email address does not exist.
The mailbox of the email address is full and can not receive any more emails.
Mailbox does not exist
The domain exists but the mailbox does not exist on the mail server.
Mail server fault detected
The mail server has been incorrectly configured
No MX servers found
No MX servers could be found for the email address
Server does not support international mailboxes
The server does not accept International characters. eg: Chinese alphabet. For further information see https://en.wikipedia.org/wiki/Punycode
Too many @ signs found
The email address contains more than one @ symbol.
Possible spam trap detected
Do not email, this email address is a spam trap.
We were unable to retrieve any information on the email address.
The email server is employing greylisting. For more information, see https://en.wikipedia.org/wiki/Greylisting.
Domain is well known disposable email address
This is a disposable email address, do not email.
Mail servers that behave in an unpredictable way, giving false results.
Server is catch all
The server accepts any email address as long as the domain is correct.
Transient network fault
We were unable to retrieve any information at this point in time, (try again later)