An IP address is sometimes added to blacklists due to malicious activity such as spamming or sending bulk messages. If your mail server is blacklisted, some of your emails may not be delivered.
Please note that according to clause 6.4 of the User Agreement, we cannot influence third-party restrictions. If your IP address is blocked, you may consider purchasing an additional IP address or using the methods outlined below to remove the IP address from blacklists.
It is important to note that Gcore does NOT tolerate the use of its services for distributing unsolicited emails, chain letters, mailbombs, or SPAM (including in particular unsolicited bulk e-mail (“UBE”) and/or UCE) in accordance with the Acceptable Use Policy. You may find more information on this within the Legal Information section.
Avoid being blacklisted
To reduce the chances of getting blacklisted, please follow these recommendations while using Gcore services for email purposes that are not associated with spam or any other related activity:
- Ensure that your emails include an unsubscribe link.
- Make sure all recipients are authorized to receive emails from you.
- Check that all DNS records are configured correctly.
Check if your IP is blacklisted
To check if your IP address has been blacklisted, we recommend using one of the IP checking services, such as https://mxtoolbox.com/blacklists.aspx. Here's how:
1. Open the website and enter your IP address in the Server IP or Domain field, and click Blacklist Check.
Your mail server IP will be checked against more than 100 blacklists.
2. If your IP address is blacklisted, you will receive the following message and a list of blacklists.
3. Click the Details button for information about the blacklist, the reason for blocking, and possible ways to get delisted. 
4. Contact the blacklist and provide details about possible reasons for the blocking, as well as the start date of using Gcore services.
5. Wait for a response.