Have you verified an email address and received back the result 'Unverifiable - Unpredictable System?'
This means the domain in question is using a service where we are unable to verify the integrity of the email address. That service is LinuxMagic.
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, for example, 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 creates its own blacklists to use in the products; MagicMail and MagicSpam. These products work in reverse to normal blacklists - actively harvesting IP addresses and charging for removal. Sometimes one of our IP addresses is added to the LinuxMagic blacklist. That's why when we validate an email address that is on a network that refers to a blacklist curated by Linux Magic, we return the result; 'Unverifiable - Unpredictable System.
LinuxMagic throttles genuine email communication and charges legitimate companies to have IP addresses removed from its list. To get around problems caused by it, we recommend creating a whitelist for trusted 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 interact with the trusted domains.
A note about choices for blacklist providers
If you are looking for a blacklist provider to help screen your incoming mail from spam, we recommend Spamhaus (https://www.spamhaus.org/). Spamhaus blacklists are responsible for blocking the vast majority of spam and malware sent out on the Internet. Spamhaus data is 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.
As you can tell we're big fans of Spamhaus and we believe you should have to pay to be taken off a blacklist if you're a legitimate business.