Overview
When starting Secure IMAP service in Kerio Connect, the port might be already occupied by another service or process. Other preinstalled Windows programs may cause start problem for IMAPS port.
By default, the Debug log generates the following entry:
Service IMAPS started on port 993, listens on all interfaces
Prerequisites
Kerio Connect installed on Windows
Diagnosis
It might happen the different processes are listening on the same port. The netstat
-ano command may show similar output:
TCP 0.0.0.0:993 0.0.0.0:0 LISTENING 3084
TCP 0.0.0.0:993 0.0.0.0:0 LISTENING 1944
TCP [::]:993 [::]:0 LISTENING 1944
The last number in each row represents PID (process identifier) number. In a normal environment, when there is only Kerio Connect installed, there will be no second application using the same port. Usually, the PID of Kerio Connect Mailserver in netstat output can be identified by port 4040, which is the default for Kerio Connect Webadmin.
TCP 0.0.0.0:4040 0.0.0.0:0 LISTENING 1944
Such analysis may help to find the other application (PID - 3084) occupying the same port resource.
Solution
- Open Windows Task Manager -> click More Details.
- Open Details tab -> sort the processes by PID and identify the corresponding task.
- End the necessary task.
- Restart the Kerio Connect IMAP service.
- (Optional) If the users are unable to connect using IMAPS from external networks, make sure there are no incorrect service access restrictions applied.
Confirmation
Secure IMAP service is listening to Kerio Connect email client connections.