Free provides a postmaster website support page to help senders encountering delivery problems to their customers. Free also provides a blocklist lookup feature, as well as details on common SMTP error codes, and instructions for how to mediate delivery problems.
- Determine if your IP address is listed on their internal blocklist. Free automatically delists your IP address after 24 hours, but listings recur if the issues are not resolved. It is possible for listings to recur for a few days after you resolve the issue as your reputation metrics normalize to lower levels.
- Depending on the severity of the issue, Free may require you to implement a confirmed opt-in (COI) consent method. You may want to temporarily adopt a more aggressive consent method prior to being asked, so if you send a support request, you can let Free know you made the change to show your intention of being a responsible sender.
- Review the SMTP error codes for additional information about sending issues.
- Using your SMTP error codes, determine if your connection and throughput settings need adjusting. Free is sensitive about senders using up their resources as it makes them less effective delivering legitimate email to their customers. Adjust your connection and throughput settings to reduce the load on their servers until you stop seeing the SMTP 421 error codes.
- Ensure Sender Policy Framework (SPF) is passing verification. Check a few campaigns using the Gmail CoreSeeds for the Authentication-Results: header. Troubleshoot your SPF record if you see a result other than spf=pass.
- Ensure all unknown users are removed after one bounce.
- Scan your systems to ensure you are not hosting or sending viruses or content with links to websites known for distributing malware.
- Free has a public escalation process to investigate delivery problems and remove blocks, however, not every request for support receives a response. Prior to contacting Free, make every attempt to identify and fix the cause of the issues. Send a sample of any rejected email to email@example.com with your company name, IP address, sending domain name, campaign subject line, date sent, error message you received, and a description of the issue. Send another email to firstname.lastname@example.org with the same information (without the sample) and be sure to detail any steps you took to correct the issue.