Server webmail is overloaded or inaccessible

Overview

The webmail interface is inaccessible due to excessive server stress, and that makes it difficult or impossible to proceed with performance troubleshooting.

Solution

Pre-requisite: Admin access to the Kerio Control

A common cause of performance issues is large mailboxes (more than 20 GB of total data size or folders with 10000 or more items).

To address this:

1. Isolate the machine to check if it is a core performance or an integration issue
   • Shut down all services except for HTTPS to devise a ‘maintenance mode’
     • Go to Settings --> Services
     • Right Click on each Service (Except HTTPS) --> Click Stop
       
     • Change the HTTPS Port so only you can access it to perform maintenance tasks. This will prevent other devices from accessing the server for synchronization, so that you can perform maintenance tasks without the performance issue getting in the way.
       • Right Click on HTTPS (Secure HTTP) --> Click Edit
         
       • Change the port in 'Properties' by adding or editing the port that can access the service
         
   • An alternative option is to disable service access via the Security Policies
     
     • User Access Policies --> Add Restriction to Deny certain services
       
     Note: Adding temporary security restrictions for troubleshooting is generally more complex than disabling the services entirely.
2. Access the Webmail UI through a browser (Firefox recommended)
   • Enter the following in the navigation bar: http://localhost:<Port added for HTTPS>
   • Clean the identified folders in the affected accounts, to reduce mailbox size
3. Once done with maintenance, reactivate the services, reset the HTTPS port, and/or remove any temporary security restrictions to restore access to client devices.