Unable to send emails from Hosting Server using zoho SMTP

Unable to send emails from Hosting Server using zoho SMTP

I am hosing my domain email hosting with Zoho and web hosting with Byethost. 
1. MX entry updated in Byethost earlier and normal emailing is working fine.
2. Sending email script, using Zoho smtp with zoho credentials from my development server is working.
3. With the same script uploaded, it was working with Byethost server as well, as soon as I deployed it yesterday.
But suddenly from today my script is unable to send emails from Byethost using zoho SMTP, whereas with the same script I can send emails from my local development server using Zoho SMTP. I have tested with Google SMTP and working well in my Hosting provider. 

I am using Code igniter with the following config: 

$config['protocol'] = 'smtp';
$config['smtp_host'] = 'ssl://smtp.zoho.com';
$config['smtp_user'] = ' no-reply@mydomain.com';
$config['smtp_pass'] = '*********';
$config['smtp_port'] = 465; 
$config['smtp_timeout'] = 50;

What could be the my error?