So you just verified an email address and received back the result Unverifiable -

Unpredictable System, What does this mean?

Basically it means the domain in question is using a service where we are unable to verify the integrity of the email address in question. For example MagicMail and MagicSpam which are both programmes from LinuxMagic employing blacklisting of our IP Addresses.

Our systems can contact mail servers at high speeds with repeated queries, so sometimes email validation can be mistaken for a threat. It takes time and patience to get to know blacklist triggers and avoid being listed.

Lots of companies employ blacklisting to stop their systems being abused, here at Email Hippo, we have a blacklist of every disposable email address domain, using this blacklist we are able to stop people signing up to Email Hippo using a disposable email address.  

Linux Magic is creating its own blacklists to use in their products MagicMail and MagicSpam, unfortunately it is looking like you will be parting with more than just your time if you want to get off their blacklist.  Unlike Spamhaus ( a credible internet blacklist provider and free to use. Check them out here ) LinuxMagic wants you to pay for your removal from their blacklist as well as convince the curators that your IP address isn't being used to perform any email marketing.

What we recommend doing is creating a whitelist for companies in your database, when you know the email address is correct but Email Hippo returned it as an Unverifiable - Unpredictable System. This will allow you to still let the domain to sign up to your service or allow you to still email them.

As for people looking for a premade blacklist for blocking spam and don't want to have to pay a yearly licence to a company who does not provide as good service as free to use companies.

We recommend Spamhaus ( On 02 July 2018 the Spamhaus blocklists are protecting an estimated 3,022,130,000 ( Three billion, twenty two million, one hundred and thirty thousand) user mailboxes and are responsible for blocking the vast majority of spam and malware sent out on the Internet. Spamhaus data is today used by the majority of the Internet's ISPs, email service providers, corporations, universities, governments and military networks.

They also work closely with with Law Enforcement Cyber Crimes teams, assisting in investigations into spam senders, phishing, botnets and malware operations, and compiling profiles, backgrounds and evidence on spam gangs and spam operations.

Spamhaus's main LEA ( Law Enforcement Agencies) working partners are:

National Cyber-Forensics and Training Alliance

Federal Bureau of Investigation

Spamhaus is a member of the main Law Enforcement task force dealing with international cybercrime issues, and a member of the main Internet Industry work groups set up to deal with abuse issues. These include:

London Action Plan (LAP)

Messaging Anti-Abuse Working Group

Awards presented to Spamhaus include:

Cyber Crime Fighter Award

presented to Spamhaus by the Federal Bureau of Investigation's National Cyber-Forensics and Training Alliance (NCFTA).

Internet Hero Award

presented to Spamhaus by the Internet Service Providers Association (ISPA) (2003)

Greatest Contribution to anti-spam in the last 10 years

presented to Spamhaus by Virus Bulletin Magazine.

As you can tell we're big fans of Spamhaus and while we don’t mind other companies wanting to help clean up the internet, we personally don't believe you should have to pay to be taken off a blacklist if your a legitimate business.