Letter delivery: why letters don't arrive and how to fix it

On the Kwiga platform, you can send different types of emails: regular campaigns, emails via automation, and system messages (activation, payment confirmation, practice review notifications, etc.). But sometimes emails do not reach recipients.

What is a bounce (Bounce)

A bounce is a delivery failure that occurs when the mail server cannot deliver a message to the recipient.

When you send an email via Kwiga, it first goes to our servers and is then passed to the recipient's mail server (Gmail, Outlook, etc.). If the recipient's server cannot accept the email for any reason, it sends back a message explaining the issue. This message is called a bounce. 

Below, we will look at different types of bounces and the most common reasons why emails do not reach recipients.

1. Permanent bounce (Hard Bounce)

This is a final delivery failure – the email will never be delivered. Main reasons:

• Non-existent email address – the most common reason

• Non-existent domain – the domain in the address does not exist

• Blocked sender – the recipient has blocked your address

• Server rejection – the mail server permanently rejects emails, etc.

2. Temporary bounce (Soft Bounce)

This is a temporary issue that can be resolved. Main reasons:

• Mailbox full – the recipient has run out of space

• Temporary server issues – the server is unavailable or overloaded

• Large email size – the email is too large

• Spam filters – the email went to spam

• DNS issues – temporary problems with domain settings, etc.

Why the email is no longer sent to the client

If a bounce was previously recorded for a client's email address, the Kwiga system automatically stops sending emails to that address. This is an important protection mechanism that works in the interests of all platform users, including your other students.

When you keep trying to send emails to such invalid addresses, email providers start to consider you a spammer. This may result in your emails going to spam even for clients who are expecting them.

In addition, this helps comply with email provider policies. Gmail, Outlook, and other services may block a sender who ignores bounces and continues sending emails to non-existent addresses. 

How to resume sending

Sometimes the situation may change. For example, a client cleared their full mailbox. In such cases, email sending can be resumed.

If the client told you that the issue has been resolved, contact Kwiga Support. Be sure to specify the exact email address for which sending needs to be resumed, and describe what was done to resolve the issue. For example: “The client confirmed that they cleared their mailbox.”

Support will analyze the situation, check the bounce history, and, if possible, resume email sending to the specified address.

What to do if a student entered the wrong email during registration is described in a separate article.

Checking the database before import

If you plan to import an email database for campaigns that you have been collecting for a long time, we strongly recommend checking its quality before uploading it to Kwiga.

Before importing, you should remove obviously incorrect addresses with typos, without the @ symbol, or with non-existent domains. For large databases, it is useful to use special email validation services that check whether addresses are valid. 

Note: If necessary, you can also contact Kwiga Support for additional консультации on verifying your contact database (may be charged separately).