Basically, when someone places an order and they are using GMAIL account, such customers do not receive any order confirmation, invoice or tracking information. 72 hrs later I receive bounce back
Delay reason: SMTP error from remote mail server after end of data: [MY SERVER IP ADDRESS] Our system has detected that this message is suspicious due to the very low reputation of the sending IP address. To protect our users from spam, mail sent from your IP address has been temporarily rate limited.
Emails get bounce back only for GMAIL accounts. Hotmail, Yahoo are all fine get delivered. Also, my server IP is not blacklisted anywhere.
However, I am able to send email to GMAILaddresses using webmail application such as roundcube and horder.
Any idea how to fix the issues with default Magento email not being received by GMAIL accounts?