In today's digital world, email communication is a critical component of both business and personal interactions. Therefore, encountering an email delivery problem, such as the error message 550-5.7.1 indicating that Gmail has blocked your message due to the low reputation of the sending domain, can be highly frustrating. This article will focus on analyzing this issue and providing specific steps to resolve it.

1. Understanding the 550-5.7.1 Error Message

The 550-5.7.1 error message from Gmail is a typical example of measures implemented by email service providers to protect their users from spam and malicious emails. The message states that the sending IP address (in this case, 149.62.151.169) has a very low reputation and, therefore, the message has been blocked.

2. Factors Influencing Domain Reputation

Domain or IP address reputation depends on various factors, including:

• Rate of Spam Complaints: A high number of complaints from users can negatively impact reputation.
• Email Content: Emails containing malicious links, suspicious attachments, or classified as spam can lower reputation.
• SPF and DKIM Records: Incorrect or inadequate configuration of these records can lead to delivery issues.
• Sending Frequency: Sudden increases in the volume of sent emails may be deemed suspicious.
• Blacklists: If your IP address or domain is on a blacklist, it significantly affects your reputation.

3. Steps for Resolution and Prevention

To address and prevent email delivery issues, we recommend the following steps:

• Check Blacklists: Verify if your IP address or domain is listed on any blacklists. There are online tools like MXToolbox that can help with this.
• Optimize SPF and DKIM Records: Ensure that your SPF and DKIM records are correctly configured, which helps demonstrate the legitimacy of your emails.
• Gradually Increase Sending Volume: If you plan to increase the volume of sent emails, do so gradually.
• Regular Review of Email Content: Ensure that your emails are relevant, well-structured, and free from suspicious elements.
• Respond to Complaints: Actively monitor and respond to complaints regarding your emails.

The 550-5.7.1 error message serves as a warning that attention needs to be paid to the reputation of your sending domain or IP address. By implementing the above steps, you can improve your reputation and ensure that your emails are delivered to their recipients. It's always important to remember best practices for email sending and maintain good relationships with email service providers.