When sending emails from the Microsoft Outlook client using the Kerio Connect email, the mails remain in the Outbox. The error seen in Outlook's Send/Receive > Show Progress dialog is
Error (0x80048002) while executing the task "Kerio Connect (KOC Offline Edition) - Messages are sent: The task was aborted before completion. The issue is not seen when the same user is sending mails from Kerio Connect Webmail or from any other computer.
There are 2 different sets of steps that should be performed to resolve this:
Only One Installation of Microsoft Outlook is Available
Ensure that there is only a single installation of the Microsoft Office products on the machine where the issue is seen. Below are the steps to find and remove other installation/s:
Under Control Panel, check if the option Mail is listed twice. It may appear as showing Mail and then another entry showing something similar to Mail (Microsoft Outlook 2013 32-Bit).
The fix is to remove one of the installations of Microsoft Office.
Go to Control Panel > Programs > Programs and Features. Look for 2 installations of Microsoft Office. If you see 2 installations of Microsoft Office, then one installation needs to be Uninstalled.
To determine which one, there are a couple of options:
Look at the installation dates. Most computers come with a trial installation of Office, and the customer may have installed their own version of Office, look at the installation dates, and the one that is oldest, is the one that came with the system and should be removed.
Look at the description and see if one of the installations is en-us or something similar to it. That would be the indicator that it is the proper installation and that the one without en-us should be uninstalled.
Once one of the installations has been removed, reboot the computer. In most cases, the remaining installation needs to be repaired so that it shows those Office applications.
Reinstall Kerio Outlook Connector
The steps outlined in the Reinstalling Kerio Outlook Connector article should be followed on the machine where the issue is seen to have a fresh install of it on that machine.
The user will be able to see only one Mail option in Control Panel and be able to add the user's Kerio Connect account using the Kerio Outlook Connector and they will be able to send their emails using Outlook.