What Is smtp error: could not authenticate.?
“smtp error: could not authenticate.” is a type of error that indicates that the client couldn’t authenticate with the email server. There are several reasons why this error occurs, including:
- The user didn’t enter the right credential while logging in; invalid username and password.
- The user failed to verify while enabling the multi-factor authentication mechanisms, the Unsupported authentication method.
- You didn’t have the proper SMTP settings configured; your account is disabled.
How To Fix ‘smtp error: could not authenticate.’? Causes With Solutions
Now, after knowing the reasons for the ‘smtp error: could not authenticate.’ error, you will want to know how to fix it. Well, as there are various causes, let’s learn about each with their solutions.
1. Incorrect SMTP Authentication Details
Regardless of what mail server you use, there is an authentication system to it that validates users to allow them to connect and send emails.
Whenever you forward or send an email from the script, the mail server tries to confirm the user’s identity by checking the account username as well as password.
Suppose this authentication gets failed by the mail server. In that case, the mail server will not allow the connection, and users get the “smtp error: could not authenticate” error.
Solution For Incorrect SMTP Authentication Details
You can easily solve this cause of error by ensuring that the username and password you have entered are valid. This way, you’ll know the right username and password are delivered in the mail script.
If you have a case of default email accounts, make sure to provide the full username in the application.
In addition, if you have recently changed your password, ensure to update it in the email application.
2. Incorrect SMTP Host And SMTP Port
It is important that you enter mail server credentials in the “$mail–>Host” part of the email application.
If we take an example, suppose you are the user of Gmail as the mail server. In that case, your hostname has to be “smtp.gmail.com.” You’ll usually face such an error when you type in your hostname. Furthermore, you can also suffer this error if there is an inactive mail server.
Now, talking about the port number, generally, the default SMTP port no. is 25. However, there are a few mail servers that use custom ports, like 587, in order to prevent spam. In addition, some mail servers are configured in such a way that they only allow emails through SSL port 465.
There is also a possibility that some providers will restrict access to the SMTP port by following firewall rules. So, you may have email delivery errors due to firewall restrictions or wrong input of port entry in SMTP settings.
Solution For Incorrect SMTP Host And SMTP Port
Firstly, to solve this error, make sure to confirm the DNS connectivity of your mail server. To do this, write in the command “dig mail.domain.com.”
Next, to verify the connectivity to your SMTP port and check the right SMTP port, you have to write the following command: “telnet domain.com 25.”
After that, make sure to confirm if you have the correct SMTP settings in the application. In addition, verify that you’re using the proper SMTP host and port. Furthermore, if there are firewall restrictions, your IP has to be whitelisted in the firewall.
3. SMTP Encryption Settings
Well, since security is such a major concern, it’s obvious that most users prefer using SMTP with encryption for secure email transmission. But, you must know there are two encryption protocols: SSL and TLS.
However, there are a few mail servers where the support for SSL/TLS might not be active. Furthermore, chances are your current SSL certificate might be expired. And, in such cases, if you specify encryption in your application, you’ll face the “smtp error: could not authenticate” error.
Solution For SMTP Encryption Settings
Firstly, to solve this error due to SMTP encryption settings, you need to ensure that PHP and Apache are correctly configured on your server. You can check this using commands like “openssl” and “mod_ssl,” which help with SSL working on the server.
In addition, you have to confirm the validity of the SSL certificate of the mail server by using the following command:
“openssl s_client -connect mail.example.com:25 -starttls smtp”
So, ultimately to get rid of this error, you can either remove the SMTP settings encryption or correctly configure SSL for the server.
4. Google Blocking Insecure Access
Another possibility of you facing the “smtp error: could not authenticate” error is because of the strict security restrictions which Gmail enforces.
Suppose the application you’re using doesn’t meet the security standards of Gmail. In that case, it may block your access, as these apps are pretty vulnerable to breaking into.
The reason why you’ll receive this error is that Google sees your username and password as insecure.
Solution For Google Blocking Insecure Access
If the blocking by Google is your source of error, the first thing you have to do is reconfigure your app, as it will help in meeting the security standards of Google. However, if this method doesn’t work, you can use the following steps to decrease these security restrictions:
- Firstly, sign in to your Google admin console.
- Then, head to the “Security” section.
- After that, select the “Basic settings” option.
- Next, head to the “Less Secure Apps” section.
- Finally, hit the “Allow less secure apps” button.
5. Expired Password
While this is not common, you may face an expired password situation. There are a few servers that come with an auto-expire password setting. And normally, the app maintainers forget about updating their passwords in time.
So, in such cases, when the app tries to connect, the mail server cannot validate the password. And thus, you face an “smtp error: could not authenticate” error.
Solution For Expired Password
You can face this kind of error if you somehow miss the notification telling you about the password expiry. However, the solution is quite simple.
If an expired password is the source of the error, simply reset your password. In addition, make sure to update the new password in the email application.
Other than that, confirm if the notification email is set properly. Furthermore, if you want, you can get rid of the password expiration set for your mailbox.
Conclusion
“smtp error: could not authenticate” is usually faced by individuals who send emails through PHPMailer while using SMTP authentication. A user will face this error if the mail application cannot establish an STMP connection while sending mail via the mail server. So, now after knowing the usual causes and solutions of this error, we hope you can send emails without facing any errors.
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