At times, the IP address from which you send emails may be marked as spam sender or blacklisted by email service providers, e.g., Gmail, Yahoo, Yandex, etc. As a result, external users may receive emails from Kerio Connect marked as spam. The following error may appear in the logs:
Our system has detected an unusual rate of unsolicited mail originating from your IP address
This article provides the steps to resolve this issue so that the emails are no longer marked as spam or blacklisted.
- Access to Kerio Connect Webadmin
- Access to Domain Records configuration
Depending on the email traffic you're sending (bulk or marketing emails, etc.), the Kerio Connect Public IP address may become blacklisted or marked as a Spammer host in the Known Spam Relay Blocking systems (like SORBS).
From time to time, the user accounts may become compromised, which generates big traffic of spoofed emails, which leads to a decrease in Domain and IP address reputation.
The sender score is in your own control and responsibility and in most cases, not an issue caused by the Kerio Connect configuration.
To improve your emails' reputation and prevent messages from being marked as spam by other vendors, it's recommended to follow the process below.
- Configure the SPF record.
Note: There are multiple ways to create an SPF record. It is recommended to include the IP address of your server to the SPF record.
We suggest using the following format (replace
188.8.131.52with your real IP address):
v=spf1 mx ip4:184.108.40.206 -all
- Configure DKIM and DMARC records.
If you are not sure how to create such records, please contact your Domain Registrar.
In the case of Gmail, if your emails are still being blocked by them after configuring the above, then you can answer the questions on their Help Center article Troubleshooting for senders with email delivery issues and then fill out their contact form.
Emails should not be rejected by other providers any more, while domain reputation should increase.
Note: Some external email providers have delisting periods, after which the email Domain and IP address becomes clean and is removed from the Blacklist. For more information, please contact the Blacklisting Authority (SORBS, Spamhaus, etc).