Overview

You may receive similar non-delivery emails (NDR) with the following message:

4.5.3 Too many recipients, maximum recipient count <number> exceeded.


This article explains why this error occurs and how you can troubleshoot it in your KerioConnect instance. 

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Root Cause

This error may occur when the email was sent to a large number of users, which is higher than the maximum allowed number on the SMTP server (in this example, the maximum number is 25 email addresses).

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Process

1. Open Kerio Connect Webadmin and navigate to Configuration > SMTP Server.
2. Click on the Security Options tab.
3. Increase the Max. number of recipients in a message value according to your needs.
4. Click Apply.
   
   
   
5. Resend the email to the recipients.

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Confirmation

The email should be received by all recipients, and no NDR message should be received.

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Additional information

Securing SMTP server

 

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