Custom email service timing out

Hi folks,

I setup a Zoho Email service with its SMTP settings and apparently it's nothing wrong with it. When I try to test this service using API Docs, I got the following error:

"error": {
"context": null,
"message": "Connection could not be established with host smtp.zoho.com [Connection timed out #110]",
"code": 500 ... }

I've checked my email configurations and also it's the same properties I'm using for my personal email. Server is up and running, username and password are correct, as well as the port number. BTW... I'm on 2.1.2 version.
Please advise...

Thanks in advance.