If your emails are sending successfully to some recipients but not others, it usually means the messages are being blocked, filtered, or rejected by the receiving mail server. Email delivery depends on several factors such as spam filtering, DNS records, and the recipient’s email provider. Below are some common reasons why this may happen.

The recipient’s spam filter may be blocking the email

Different email providers have different spam filtering rules. In some cases, your message may be delivered to the recipient’s spam or junk folder instead of their inbox. 

• You can ask the recipient to check their spam folder or add your email address to their safe sender or whitelist.

Missing or incorrect email authentication records

Email providers often check DNS records such as SPF, DKIM, and DMARC to confirm that a domain is allowed to send email. 

• If these records are missing or incorrectly configured, some servers may reject the email or mark it as spam.

• How to access your DNS through Rebel 

• How to access your DNS through Plesk 

The recipient’s mail server may be blocking your IP or domain

Some organizations have strict mail server rules and may block messages from certain servers, IP addresses, or domains. If your email works for most people but consistently fails for one specific recipient or company, their mail server may be blocking it.

The message content may trigger spam filters

Certain email content can trigger spam filtering. For example, emails with too many links, attachments, large files, or certain wording may be flagged as suspicious by some mail providers.

Temporary delivery issues

In some cases, email servers may temporarily reject messages due to server load, maintenance, or security checks. When this happens, the sending server may retry delivery automatically.

If you are experiencing issues or have any questions, please feel free to contact our support team at service@rebel.com anytime, or you are able to speak to a live agent through chat or call 1-866-642-1232