DATA Not accepted from server

I am getting the below error when trying to send a mail from my opencart store hosted in digitalocean.

PHP Notice:  Error: DATA not accepted from server! in /var/www/html/system/library/mail.php on line 417


Opencart version - 2.0.3.1
Email Settings:
  Protocol : SMTP
  Hostname : ssl://smtp.zoho.com
  port : 465
  Timeout : 15

FYI: I have already tried to fix this by following the below link:

https://help.zoho.com/portal/en/community/topic/solution-of-problem-553-relaying-disallowed-data-not-accepted-from-server-for-opencart