SMTP STARTTLS Errors Causes, Fixes & How to Ensure Secure Email Communication
Being exposed to email security risks is something we all want to avoid; security risks such as man-in-the-middle (MITM) attacks, where attackers intercept and manipulate email traffic, are the bane of all email marketer’s existence. There are the basics of ensuring a configured DNS and SMTP setting, but some errors go deeper than that. Some […]
SMTP Error 421 4.7.26 – Email Rate Limit Exceeded: Causes & Fixes
Ensuring that your emails land in recipients’ inboxes is getting more and more complex. Sending limits and anti-spam measures are being imposed by Internet Service Providers (ISPs) and Email Service Providers (ESPs) to prevent unwanted emails from reaching users. As a result, errors sometimes occur for even legitimate senders—affecting their email campaigns. The SMTP Error 421 4.7.26, […]
SMTP Error 421 4.4.3 – Routing Server Failure Causes & Solutions
You may often see the error: SMTP transient error: 421 Service Not Available And think that you can just wait it out. This can be true for some of the SMTP email error 421, but its variants may have severe repercussions on your email deliverability. One of its variants that may require immediate attention is […]
How to Solve SMTP Error 421 4.4.5 – Server Congestion Issues
Email is key for both personal and professional lives. But when an email doesn’t make it to its recipient, it can cripple the business, lead to missed opportunities, and ultimately loss of revenue. Server congestion, or SMTP error 421 4.4.5, happens when an email server is overloaded with incoming or outgoing email requests. This might […]
Fixing SMTP Error 421 4.4.2 – Bad Connection What You Need to Know
The most difficult part of creating email content and developing email marketing strategies is actually crafting the campaign right? Not really. If you are an email marketer or have done some campaigns, you understand that there is more to email marketing than simply creating content, strategizing campaigns, and then hitting send. You need to employ […]
The Science and Process of Warming Up Newly Created Email Domains
Crafting effective marketing email content is just one of the fundamentals that can make an effective email outreach successful. In the realms of email marketing the technical aspects are just as crucial as the marketing ploy; our research team devoted their time to understanding the best and most helpful technical factors that can help every […]
How SMTP AUTH Mechanisms Affect Email Deliverability and Security
SMTP Authentication (SMTP AUTH) is not only a fundamental mechanism that protects your emails against spoofing and phishing attacks. It also has a direct contribution to your email deliverability and brand recognition. Depending on how well you set up your SMTP AUTH you are less likely to experience SMTP errors related to authentication failures —potentially […]
SMTP Error 421 4.3.2 – Service Shutting Down Causes & How to Fix It
There are tons of SMTP related errors that an average email user can encounter. Some of them can be due to IP reputation concerns, while others are rooted and are likely the result of a temporary errors failure — retryable errors. One of these temporary errors is the SMTP error 421 4.3.2 (Service Shutting Down), […]
SMTP Connection Encryption: The Key to Secure & Reliable Email Delivery
One of the top channels of communication for businesses is email, which unfortunately makes it one of the prime targets of cyberthreats like phishing, data interception, and spoofing. Encryption is the answer. Without it, emails are transmitted as plaintext over the Internet where people can steal sensitive information. SMTP (Simple Mail Transfer Protocol) is the […]
SMTP Error 421 4.4.1 – No Answer from Host: What It Means & How to Fix It
The SMTP Error 421 4.4.1 – No Answer from Host error indicates that your email server is unable to connect with the recipient’s server. This is just one of the many problems that can deeply affect email deliverability resulting in delays or even undelivered messages. So what should an email sender do when this message shows […]
