550-5.7.26 GMAIL Error: Email blocked because sender was unverified
Posted: Tue Apr 22, 2025 9:35 am
Gmail Email Senders Guide and Error Code Solutions
1. Introduction
Users please note that Gmail has officially rolled out that users will receive the following error: Another variant of this error is this 550-5.7.26 Sender not certified Gmail error means that buy bulk sms service your domain lacks email certification implementation. Starting February 1, 2024, Google will gradually enforce new email sender guidelines. These guidelines require bulk senders to enable DMARC, SPF, and DKIM for their domains. General senders are no exception as they must implement SPF or DKIM. In this article, we will explain how to easily and quickly deploy these complex-sounding email protocols! We will also provide you with ways to test your current compliance. By the end of this article, you will be able to fix the "error. If you are not compliant with Google's email sender requirements, Gmail may block you from sending emails. These requirements are mandatory, and senders who do not comply with the requirements may be blocked by Gmail. If some of your non-compliant emails are still being sent, then you are not innocent either! Google is rolling out the requirements in a gradual manner. This means that in the future Gmail will definitely block all non-compliant emails.
2. Gmail Email Senders Guide
Here are some reasons why Gmail will block emails from your domain in 2024:
If you send fewer than 5,000 emails per day, Gmail may block you from sending emails if:
If you send more than 5,000 emails per day, Gmail may block you from sending emails if:
In addition to not following the above Gmail email sender best practices, here are some more triggers:
Gmail can block outgoing messages that contain spam content. Poorly written and grammatically incorrect messages are detected as spam. Therefore, it is recommended to check the grammar issues in the content before sending the message. To accurately check for all types of grammatical flaws, you can use the grammar checker to find and fix all grammatical errors.
Additionally, if you include an attachment that contains a virus in a message, Gmail will block the message. Gmail also treats emails with suspicious content as harmful. This includes emails that are planning scams, selling illegal items, or promoting dangerous content.
Your domain reputation is very important. If your sender reputation is bad, Gmail may block you from sending emails in the future. This doesn't necessarily mean that all your emails are bad. It just means that your domain has been reported as spam in the past by various sources. This can cause your sender reputation score to drop.
If your domain is included in an IP block list, Gmail may block you from sending emails. You can sign up for our reputation monitoring service to see domains that are included in the block list. Getting whitelisted will automatically improve your Gmail email deliverability.
Gmail takes relevance of emails very seriously. In Google's 2024 Email Sender Guidelines, they ask senders to send only emails that are valuable to the user. This means, you shouldn't send an email advertisement for female perfume to a male recipient. This goes against the user's interest as the email may not be valuable to him. Instead, keep the user's interest in mind while sending the email.
If Gmail is blocking your email, you may receive the following Gmail error message:
In the example shown above, Gmail has blocked the sender's email because it was unauthenticated. In the message, Gmail mentions that the message failed both SPF and DKIM - causing the message to be rejected. This is likely because PowerDMARC customers can. Our human-readable reports provide visibility into your mail flow so you can quickly spot delivery issues with your email!
3. Solve Gmail errors
After you have determined that Gmail is blocking your emails, it’s time to fix this error. Let’s see how to fix it:
To fix 550 5.7.26 and Gmail email sending issues and stop Gmail from blocking emails, follow these steps:
To resolve the "Gmail email blocked due to unverified sender" error, you must set up SPF. SPF helps you verify the source of the sending, establishing it as a trusted sender. You can implement SPF using a DNS TXT record created with SecurityGateway. Once created, visit the DNS Management Console to publish the SPF record.
1. Introduction
Users please note that Gmail has officially rolled out that users will receive the following error: Another variant of this error is this 550-5.7.26 Sender not certified Gmail error means that buy bulk sms service your domain lacks email certification implementation. Starting February 1, 2024, Google will gradually enforce new email sender guidelines. These guidelines require bulk senders to enable DMARC, SPF, and DKIM for their domains. General senders are no exception as they must implement SPF or DKIM. In this article, we will explain how to easily and quickly deploy these complex-sounding email protocols! We will also provide you with ways to test your current compliance. By the end of this article, you will be able to fix the "error. If you are not compliant with Google's email sender requirements, Gmail may block you from sending emails. These requirements are mandatory, and senders who do not comply with the requirements may be blocked by Gmail. If some of your non-compliant emails are still being sent, then you are not innocent either! Google is rolling out the requirements in a gradual manner. This means that in the future Gmail will definitely block all non-compliant emails.
2. Gmail Email Senders Guide
Here are some reasons why Gmail will block emails from your domain in 2024:
If you send fewer than 5,000 emails per day, Gmail may block you from sending emails if:
If you send more than 5,000 emails per day, Gmail may block you from sending emails if:
In addition to not following the above Gmail email sender best practices, here are some more triggers:
Gmail can block outgoing messages that contain spam content. Poorly written and grammatically incorrect messages are detected as spam. Therefore, it is recommended to check the grammar issues in the content before sending the message. To accurately check for all types of grammatical flaws, you can use the grammar checker to find and fix all grammatical errors.
Additionally, if you include an attachment that contains a virus in a message, Gmail will block the message. Gmail also treats emails with suspicious content as harmful. This includes emails that are planning scams, selling illegal items, or promoting dangerous content.
Your domain reputation is very important. If your sender reputation is bad, Gmail may block you from sending emails in the future. This doesn't necessarily mean that all your emails are bad. It just means that your domain has been reported as spam in the past by various sources. This can cause your sender reputation score to drop.
If your domain is included in an IP block list, Gmail may block you from sending emails. You can sign up for our reputation monitoring service to see domains that are included in the block list. Getting whitelisted will automatically improve your Gmail email deliverability.
Gmail takes relevance of emails very seriously. In Google's 2024 Email Sender Guidelines, they ask senders to send only emails that are valuable to the user. This means, you shouldn't send an email advertisement for female perfume to a male recipient. This goes against the user's interest as the email may not be valuable to him. Instead, keep the user's interest in mind while sending the email.
If Gmail is blocking your email, you may receive the following Gmail error message:
In the example shown above, Gmail has blocked the sender's email because it was unauthenticated. In the message, Gmail mentions that the message failed both SPF and DKIM - causing the message to be rejected. This is likely because PowerDMARC customers can. Our human-readable reports provide visibility into your mail flow so you can quickly spot delivery issues with your email!
3. Solve Gmail errors
After you have determined that Gmail is blocking your emails, it’s time to fix this error. Let’s see how to fix it:
To fix 550 5.7.26 and Gmail email sending issues and stop Gmail from blocking emails, follow these steps:
To resolve the "Gmail email blocked due to unverified sender" error, you must set up SPF. SPF helps you verify the source of the sending, establishing it as a trusted sender. You can implement SPF using a DNS TXT record created with SecurityGateway. Once created, visit the DNS Management Console to publish the SPF record.