Frequently Asked Questions

The following provides answers to some of the frequently asked questions about MailloX, from sales & billing to mailing & support.


Email tracking is a method for monitoring the email delivery to intended recipient. Most tracking technologies use some form of digitally time-stamped record to reveal the exact time and date that an email was received or opened, as well the IP address of the recipient.

When an email message cannot be delivered to an email address, it's called a bounce. There are lots of different reasons why emails bounce so, when it happens, a "return to sender" message is sent from the recipient's mail server to explain why.

Six Reasons Why Emails Bounce.
1. A non-existent email address
If the bounce is marked as “non-existent email address,” the email address could have a typo or the person with the address may have left the organization. There’s also a chance that the contact gave a false email address, which can be the case if you’re offering something online in exchange for an email. In this case, it’s important to review the contacts in this category and see if there are any obvious typos in the email address. If not, try to reach the contacts by other means to confirm the address. 2. Undeliverable email
If bounced emails are in the “Undeliverable” category, that means that the receiving email server is temporarily unavailable, was overloaded, or couldn’t be found. A server that can’t be found could have crashed or be under maintenance, so this may just mean waiting to send the email to the address again. However, if this email address repeatedly bounces on multiple emails, it may mean the server is gone for good. 3. Mailbox Full
If your contact has so many emails in their inbox that they can’t receive more, your emails will bounce back until there’s space for them. Sometimes, this can mean that the contact is no longer using that email address. As with a non-existent email address, you may want to follow up with the contact by phone or mail to check whether the address is valid. 4. Vacation/Auto Reply
If someone goes on vacation or can’t check their email, your emails to them will bounce. It’s important to note that, unlike with other bounce categories, this type of bounce means your email was successfully sent to the inbox. Carefully monitor how often this email address ends up in this category. If months go by and the person hasn’t returned from vacation, you may want to consider removing the contact. 5. Blocked email
If the email addresses are placed within the “Blocked” category, the receiving server has blocked the incoming email.

The most important factor in determining whether your message is marked as spam or goes in your subscriber's inbox is your sender reputation score. Sender reputation is associated with the IP address of the mail server you are using to send messages from. A good habit to follow before sending your bulk email is to look up the IP reputation of your SMTP service. IP reputation is the major contributor to delivery rates, especially if you are sending to the largest ISP’s, e.g. Yahoo!, AOL, Hotmail. Statistics show that 83% of the time, sender reputation is the real cause of filtering: by monitoring it you will be able to identify problems affecting your sender reputation, determine the causes, and fix them. Here are some of the major metrics ISPs look at when managing the message sent into their system: – volume of emails (illegitimate bulk mail do normally trigger spam filters) – spamtraps hits (old inboxes that ISPs reactivate specifically to trap spammers ) – invalid address rates (hard bounces) – complaints rates (how often recipients hit the “report spam” button to response to your message) The good news is that there are some online services that let you check your IP reputation. We recommend these four Free ones: Senderscore It’s the most popular. With their tool you’ll know right away what ISPs think of your email program. Just enter an IP address and you’ll get a simple score based entirely on the metrics that distinguish legitimate email from spam: volume, complaint rates, unknown user rates, infrastructure, spam trap hits and content. Senderbase Senderbase allows you to query the email and web reputation for almost any IP address sending email or Domain on the Internet. Ip reputation score is grouped into Good, Neutral or Poor. Barracuda Central The Barracuda Reputation System is a real-time database of IP addresses that have a “poor” reputation for sending valid emails. Barracuda Central maintains and manually verifies all IP addresses marked as “poor” on the Barracuda Reputation System. Reputation Authority An effective defense reputation service for email and Web security. To discover the Internet IP address from which your emails has been sent you need to analyze their headers, in particular consider the first “received” information. That’s the IP address you should monitor with these tools.

MailloX identifies the email addresses that are not functional or that do not exist. It then advices you to delete them in your mail list. This reduces bounce rate as well as increases your email reputation.