It is more often to find an error of authentication failure on your server when you try to log in. Generally, the error occurs when you fail to log in with the wrong user or password. If your mail server rejects the credentials you entered to the field of username or password, it will result in authentication failure.
As a server management service provider, our technical support team gets a lot of queries to fix authentication failure errors. With this blog, we would like to explain the different causes for the error and how our server engineers fix the “SMTP Error 535 Authentication Failed” message.
Causes for “SMTP Error 535 Authentication Failed” Message
To send the messages, the mail client uses Simple Mail Transfer Protocol (SMTP). If any inappropriate authentication is detected by the server, an error message is generated. The server shows different error messages depending on the email program. In some cases, the server may not display any error messages. Some of the common reasons for SMTP error 535 authentication failed message are:
Inaccurate Username or Password
The “SMTP error 535 authentication failed” message may occur if you mistakenly enter the wrong username or password into your program. Usually, everyone uses the same username and password as your email address to log in to your mail server.
Some SMTP servers ask for a set of credentials that are different from your email account. In this way, server security can be maintained. You can contact your mail servers administrator if you need any further assistance.
Issues such as spamming and payment dues can make your account temporarily or permanently disble. A disabled account can be a reason for authentication failed message. Hence, you should ensure your account is active by checking the status of your account. Do connect with your server support team in case of any issues.
You may have to enable the connection encrypted with SSL/TLS for some servers. If you have disabled this option, you might get an SMTP error 535 authentication failed message.
If you have authentication methods that are not supported by your mail server, there are chances to show the SMTP error. To resolve the disabled or expired IP-based authentication, you are requested to check the status of your account. Even though IP-based authentication is considered to be an uncommon error, it can result in an SMTP error 535 authentication failed message.
Methods To Resolve “SMTP Error 535 Authentication Failed” Message
- Firstly, you should log in to your control panel and check your current account status. Generally, you will receive a notification if your account faces issues if any.
- Check the username and password provided to log in to your mail server. Importantly, it is advised to change the credentials to a more secure one and also should remind them for your next login.
- Block the IP addresses that are consistently trying to log in to your account. By blocking the IP address at the server’s firewall, you can prevent their attempt to log in again.
- Enable the SMTP authentication for the server-side and client-side.
Enabling the SMTP authentication in Plesk:
- Log in to your Plesk control panel.
- Go to Tools & Settings and select Mail server Settings.
- Select the Relay Options and choose Enable SMTP services.
You can get connected to the Plesk server management service provider if you are struggling to fix the issue on your own.
Enabling the SMTP authentication in cPanel:
In WHM, SMTP authentication is disabled by default. Hence you may need to turn on the authentication on your own. For this purpose, you can follow the below method.
- Navigate to WHM and select Service Configuration.
- choose the Service Manager.
- Now you can select the Antirelayd checkbox.
For further assistance, you can contact your cPanel server support provider.
With this article, we explain the different causes for SMTP Error 535 Authentication Failed message and some easy methods to resolve the issue on your own. In general, the common cause for the occurrence of the error is inaccurate credentials. But some factors result in SMTP error. You can get help from server management service providers in case of any issues.