A user's Kerio Connect mailbox is sending emails every few minutes by itself and then, receiving emails with the message
The email account that you tried to reach is over quota in response. The subject of the email received is
Undelivered Mail Returned to Sender. This article shares some points to resolve this.
- Access to the user account from which these automated emails are being sent and received.
- Administrator access to Kerio Connect.
Since the received email says that that email account is over quota, it might be an unattended mailbox that simply tries to capture information in this manner by sending these malicious automated emails. So, below are a few different ways to make sure to stop this activity:
- The account from which these emails are being sent doesn't have anything pending in the account's Message Queue due to which it might be attempting a resend every few minutes. This can be verified by logging into the Kerio Connect administrator portal and clicking on Status > Message Queue:
- Verify that there is no additional SMTP server on the user's machine from where they are accessing Outlook. This can be one of the reasons for the constant resending of emails, which appear as being sent from Kerio Connect mail.
- Check the user's machine/laptop/PC from which they are accessing Outlook and verify that there are no other malware and/or malicious software that can be performing this activity without the user's knowledge.
After performing all these checks and making changes (if any) as required, the user account should no longer receive these over quota emails.
However, if these emails are still being received by the user, then, you need to enable the SMTP Server and SMTP Client logs in the Kerio Connect Administrator console, let the issue be reproduced (so that our Support team can gather more information as required) and open a Support Ticket for the resolution of the same.