In this blog post we will talk about the most common error “550 permanent failure for one or more recipients”. This SMTP (Simple Mail Transfer Protocol) error occurs when the recipient mail server blocks email. There are various reasons for this such as restrictions, blacklisted IP addresses, bad DNS records, etc. We cannot know what the exact issue is. Therefore, we need to investigate to confirm if it is related to the sender’s or the recipient’s mail server. In the next paragraph, we will explain what steps need to be taken to detect what makes this issue appear.
Email protocols: What is the difference between SMTP, POP3, and IMAP?
In this tutorial, we will explain the difference between the SMTP, POP3, and IMAP email protocols. Email protocol is a set of commands for sharing mail between two machines such as computers, and servers. This allows clients to send and receive email. There are a few email protocols, but the most common protocols are POP3, IMAP, and SMTP. In the following paragraphs we explain what defines them and their differences.
How to Install RoundCube on a Debian VPS
In this tutorial, we will explain how to install the latest version of RoundCube on a Debian-based virtual server. RoundCube is a multilingual IMAP webmail client developed in PHP. It has a modern interface and allows you and your users to access their email from anywhere through a web interface.