What if you get an SMTP authentication error 534 while sending an important email?

Getting errors while sending important emails always frustrates us. SMTP error 534 is one such tricky error.

Error 534 occurs mainly due to authentication failures when trying to send emails from Gmail.

At Bobcares, we often get requests to fix SMTP error 534 as part of our Server Management Services.

Today, let’s discuss this error in detail and see how our Support Engineers fix it effectively.

What causes SMTP authentication error 534?

Recently, one of our customers approached us with an SMTP error. He tried to send an email from one Gmail account to another.

All his attempts ended up in an SMTP 534 error message. But what causes this error?

This is because Google recently implemented a policy to strengthen email authentication.

Google blocks the sign-in attempts from some apps or devices that do not use modern security standards.

This keeps the accounts safe.

How we fix SMTP authentication error 534?

As we have already said, error 534 occurs when we try to access the Gmail account from any other insecure applications.

Now, let’s check how our Support Engineers fix this tricky error.

1. Enabling Allow less secure apps feature

Due to security reasons, Google usually uses the Allow less secure apps feature to protect the accounts.

We disable this security feature to resolve the error 534.

1. For that, we first login to the Gmail account.
2. Navigate to Security settings.
3. Then, we turn ON the Allow less secure apps feature.

2. Using application-specific password

‘Allow less secure apps’ setting is not available for accounts that have enabled two-step verification.

For such accounts, we generate an app-specific password. Then, we use this password as the Gmail password when setting up the “Send mail as” option.

By using this app password in /etc/ssmtp/ssmtp.conf, we disable the two-step verification using this password. This will resolve the error.

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Conclusion

In short, the SMTP authentication error 534 occurs due to authentication failures when trying to send emails from Gmail. Today, we discussed this error in detail and saw how our Support Engineers fix this error for our customers.