Troubleshooting issues related to Brevo SMTP is essential for maintaining efficient and reliable communication. In this article, we will address common issues that can arise with SMTP and provide practical solutions to help you diagnose and resolve them effectively.
Unable to log into Brevo SMTP relay
Invalid credentials
If you encounter an issue with your SMTP username or password, make sure you are using the right credentials:
- Username: Use your SMTP login email address.
- Password: Use your SMTP key, NOT an API key or your Brevo account password.
Your SMTP credentials can be found on the SMTP page in your Brevo account:
➡️ To learn more, check our dedicated article Create and manage your SMTP keys.
Wrong SMTP port
Use ports 587, 465, or 2525 to create an encrypted connection between your system and Brevo SMTP.
➡️ To learn more, check our dedicated article Which SMTP port should I use? (Port 587, 465, or 2525).
SMTP port is not open
To check if a specific port is open on a server, you need to run a command in your system console as not all hosting services may support it. This is especially useful when verifying if a port is open before integrating it with your email service or troubleshooting SMTP configuration issues.
➡️ To learn more, check our dedicated article Check if an SMTP port is open on a server.
Brevo SMTP service is temporarily unavailable
If you’re experiencing issues, the Brevo SMTP service might be temporarily unavailable. To confirm if this is a known issue, visit our Status page for updates on platform performance and outages.
Sender is invalid
Sender domain has not been authenticated
Since February 1, 2024, Gmail and Yahoo have implemented new requirements for email senders to better protect users' inboxes from spam while ensuring that legitimate emails are received. This means the sender domain used for transactional emails needs to be authenticated.
To learn more, check our dedicated article Authenticate your domain with Brevo (Brevo code, DKIM record, DMARC record).
Sender has not been verified
When creating a new sender, you need to verify it by entering the 6-digit code sent to the sender's email address. If the sender isn’t verified, it cannot be used to send transactional emails.
SMTP login is used as the sender’s address
Your SMTP login should only be used for configuration purposes, not as the sender's address. To send emails, specify a valid email address in the "From" field.
To learn how to create a sender that you can use for your transactional emails, check our dedicated article Create a new sender (From name and From email).
Emails are not sent
All email credits have been used
If your Brevo account runs out of email credits, your transactional emails will not be sent immediately. Instead, they will be placed in a queue and paused for up to 36 hours until more credits are added to your account. To learn more, check our dedicated article Why are emails added to a queue?.
To check your remaining email credits or view any queued emails, go to the Transactional page and click Usage & Plan at the top:
Transactional platform not yet activated or temporarily suspended
If the transactional platform is not activated on your Brevo account, you won't be able to send emails. To request its activation, contact our support team by creating a ticket from your account.
Additionally, the transactional platform may be temporarily suspended for several reasons, including:
-
Compromised account
If your Brevo account has been compromised, Brevo will temporarily suspend the transactional platform until you investigate the incident and secure your account.
➡️ To learn more, check our dedicated article My account has been compromised, what should I do?. -
Bot attacks on forms
If bots have targeted a form on your website, Brevo will temporarily suspend the transactional platform until you secure it.
➡️ To learn more, check our dedicated article Protect your forms from bots and spam signups.
Contacts are blocked
When reviewing your transactional logs, you might encounter "Blocked" events. These occur when emails cannot be sent to blocked contacts.
Contacts can be blocked for various reasons, including:
-
Marked as spam
If a recipient marks your email as spam, their email address may be temporarily or permanently blocked. -
Unsubscribed
When a contact unsubscribes, their email address is blocked to honor their preferences and prevent future emails. -
Hard bounce
This happens when an email cannot be delivered due to an invalid address, non-existent domain, or incorrect email format. Addresses with hard bounces are typically blocked to avoid repeated delivery failures. -
Manually blocked
You can manually block specific contacts or domains from receiving your transactional emails.
You can view the list of blocked contacts and domains on the Blocked or Unsubscribed contacts and Blocked domains pages in your Brevo account.
The recipient's ISP is not accepting your emails
Emails deferred or soft-bounced bc the recipient ISP is not accepting them.
If you are not able to authorize the domains, add the following Brevo IP ranges to your whitelist: Brevo IP ranges: improve the deliverability of B2B emails.
When reviewing your Transactional Logs, you might encounter "Deferred" and “Soft Bounce” events for a contact. These can occur when an email is sent successfully from Brevo but is rejected or delayed by the recipient's Internet Service Provider (ISP).
To address this issue, we recommend:
-
Whitelisting Brevo IP ranges and domains
Ask the recipient's organization to whitelist Brevo's IP ranges and domains to improve B2B email deliverability. ➡️ To learn more, check our dedicated article Brevo IP ranges: improve the deliverability of B2B emails. -
Authenticating your domain
Authenticate your sender domain on Brevo to help ISPs recognize the source of your emails. ➡️ To learn more, check our dedicated article Authenticate your domain with Brevo.
Dedicated IP is not configured for sending transactional emails
If you use a dedicated IP, ensure it is configured to send both marketing and transactional emails. You can check your IP configuration from the Dedicated IPs page in your Brevo account.
Brevo SMTP service is temporarily unavailable
If you’re experiencing issues, the Brevo SMTP service might be temporarily unavailable. To confirm if this is a known issue, visit our Status page for updates on platform performance and outages.
400 response generated by the API
If you encounter a 400 response while using the https://api.brevo.com/v3/smtp/email API endpoint, check our dedicated developer documentation Send a transactional email.
🤔 Have a question?
If you have a question, feel free to contact our support team by creating a ticket from your account. If you don't have an account yet, you can contact us here.
If you’re looking for help with a project using Brevo, we can match you with the right certified Brevo expert partner.