[Koha] Hi! + a newbie question about nullmailer

[tan chong hui]

Hello!
I'm a new user of Koha.A friend needs to use the system at his library and I'm helping with the backend.
Glad to join the Koha Community!

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I've had the system up and running.So far it's been smooth and fun except for a glitch.
nullmailer came to be installed together with Koha and it's been causing mail.log and mail.errto blow up to 10GB in sizes, with lines that typically look like this:
Sep  8 04:08:05 klc1 nullmailer[2290]: message repeated 694 times: [ smtp: Failed: Connect failed]

I'm not currently sending emails so I removed nullmailer altogether from the system.
Did I configure koha incorrectly during installation?
ch