SMTP. Emails are not sent via SMTP

If sending emails via SMTP through ports 25, 465 and 587 doesn't work, most likely your virtual server is suspected of sending spam.

How to solve the problem

Look in the "Support tickets" inside your personal account and check if there are any messages about blocking.


According to paragraph 2 (d) of the Acceptable Use Policy, servers cannot be used to send unsolicited emails, chain letters, mailbombs, or spam. Only mailings to users of the services located on the G-Core Labs servers rented by you are allowed. If you did not violate our Acceptable Use Policy, write to technical support — we will remove the block.

Case What to do
You are sending legitimate mailings

Ask technical support to unblock the ports and specify in your request:

   • The domain name of the service whose users you sent the mailing to

You did not send mailings, but you still received blocking messages

Check server settings. For some reason, your server is sending a lot of traffic on SMTP ports, and our system recognizes this as spam. Correct the settings and ask those. support to unblock ports. Specify in your request:

   • What the error in settings you had
   • How you fixed the error

You did not send mailings, did not receive blocking messages, but the ports still do not work

Ask technical support to unblock the ports and specify in your request:

   • That you did not receive blocking messages
   • Whether you changed the network settings or not


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