Email Validation FAQs
What will be returned if Mailbox is Full?
A: It is up to the host mail server to determine how full mailboxes are handled. Most mail servers will decline requests to a full mailbox with a temporary reject code, which will lead to a soft bounce back. Some email validation services will probably just look at the reject response and fail the email address outright, but the GBG email validations service will recognize the box as being full and will return the warning flag. The email address is undeliverable until storage space has been freed up; so delivery attempts until then will result in bounce backs, but the box may once again be deliverable in the future. There is also the possibility that the email address has been abandoned and will remain undeliverable until the mail provider deletes the account. Therefore the service describes them as unknown.
What will be returned if Mailbox is Busy?
A: When a mailbox is busy the host mail server will reject requests to the email address, which will lead to soft bounces. A busy email address is essentially an undeliverable email address. Like the 'MailBoxIsFull' flag, the service will recognize that it is only a temporary reject and will therefore return an 'unknown' IsGood response. It is unknown how long a mailbox will remain busy and undeliverable. In some cases, busy mail boxes may belong to spammers/bots that basically can cause havoc until the mail host provider disables the account or deletes it entirely. In other cases the mailbox may just simply be receiving mail at a large rate and/or may be exceeding a throughput quota.
What does “Unknown” mean in the response?
A: In general terms, an unknown return value indicates that there was insufficient information available for the Email validation service to make a definitive determination.
I’ve tried a known Disposable Email but it’s returned as Valid and DisposableEmail is false?
A: GBG are always improving the Email Validation service, as such we are unable to detect every disposable email address created. It should be noted that the Vulgar, Garbage and Bogus can often be attributed to some disposable email addresses so can act as indicators.
What will the value of IsGood be if BlacklistedDomain and Alias email address are true?
A: A blacklist check is performed separately to the SMTP check, but it alone is insufficient to return “Email is Bad” though it can reduce to “Email is Probably Bad”. Some MTA (Mail Transfer Agents) or firewalls may prevent communications with blacklisted domains even via an email address, with other MTA’s they may allow an email to go to a blacklisted domain but prevent any return. Hence the flag returned is a warning to the user to indicate they may encounter some difficulty when attempting to communicate with a black listed domain.
What is the difference between IsGood and ValidityFlag response?
A: IsGood was primary flag GBG provided, so this has been retained for existing users. ValidityFlag is the most recent encompassing flag.
What is the MisspelledSuggestion response for?
A: MisspelledSuggestion could be populated where GBG have spotted a potential typing mistake in say a domain. So for instance if the email submitted was Laura@hotmil.com, MissspelledSuggestion could return Hotmail.com
I know the email address exists, why is it saying it doesn’t or unknown?
A: Sometimes a domain can present a DNS error, depending upon the DNS time-to-live of 24 hours, then that could have prevented the service from establishing communication with the specific mail servers. However, the service does not fail a server until after three consecutive days, so unless the DNS error persisted the service should eventually communicate with the mail servers and clear it.
I know the email address is definitely a Spammer/GreyListed/Complainer… but it’s not flagged as such?
A: No list is ever complete and it would not be that uncommon that some lists lag behind what is really happening in the world, in both adding and removing emails or domains to specific lists. GBG always strive to ensure all the services are up to date and using the freshest data, however in this example, it’s not possible to have real time updates to such lists.