It can be frustrating when a message does not reach its intended recipient. While Check Cherry takes great pains to ensure a high email deliverability rate, sometimes messages get flagged as spam and do not get through. This guide will cover some reasons that this happens and what you can do on your end.

Approximately 50% of all emails that are sent each year are spam. As a result email providers such as Google, Yahoo, and Microsoft aggressively filter all incoming messages to attempt to reduce the number of unwanted messages that their users receive. While in general they are able to do a pretty good job, it is not uncommon that they incorrectly label a "good" message as spam or vice-versa. Additionally many email providers try to shield their customers from general "marketing" messages, leading to further potential for messages to be misclassified.

When an email provider decides that a message is spam or marketing, they may move it to a "Junk" or "Marketing" folder, or they may hide the message from the user entirely. Unless the user specifically reported the message as "spam", the sender typically does not get notified when this happens.

Email providers use a combination of sender reputation, message content, message frequency, and sender type in order to classify incoming messages.

"Sender Reputation" includes factors like what percent of incoming messages from a sender are labeled as spam, whether things such as SPF or DKIM are configured, and whether the sender is on any "blacklists". When sending messages using Check Cherry, these factors are generally under our control.

"Message Content" includes the text, pictures, links, and other content included in a message. Email providers will analyze the content of incoming messages to look for common spam or marketing terms, suspicious links, a large image to text ratio, and other frequent markers of spam or marketing email. Additionally they will compare the contents of the message to other spam they are seeing. For instance if they are seeing an uptick in emails that are requesting payment, they may start to block desired messages that also have similar content. When sending messages using Check Cherry, these factors are generally not in our control.

"Message Frequency" means that they look at both the volume of email from a specific email address as well as the volume of email from a host. Sudden changes in the email frequency can indicate that a sender was compromised and can result in messages being temporarily or permanently blocked.

"Sender Type": Broadly speaking, email providers will attempt to determine whether a given message is from a "personal" email account or from a higher-volume account that may be sending automated messages. Because "personal" email accounts can only send a small number of messages, they are often given a higher priority. As a result, sending a message from a personal account can sometimes result in the message being delivered even when it contains the same content.

Check Cherry follows best-practice in implementing SPF, DKIM, and DMARC which are authentication methods that help to signal legitimacy. We monitor all major blacklists in order to detect and resolve any issues with messages being blocked, and have implemented tools to monitor for reported deliverability issues with email providers and address them daily. We ensure that all outgoing messages are compliant with CAN-SPAM and related laws. We make use of dedicated IP addresses to ensure that our messages are not inadvertently impacted by other senders and we maintain redundancy to ensure that we are able to re-route messages if an IP address is impacted. Additionally, Check Cherry monitors outgoing messages for spam and has account verification practices and tools in place to ensure that compromised messages are not sent. We also track our "sender reputation" score to ensure it is the highest score available.

Lastly, Check Cherry does not support certain features that commonly lead to "spam" or "marketing" classification such as bulk newsletters or marketing messages -- instead we require that all bulk messages are sent via another service such as Mailchimp.