Some SMTP servers ask for a set of credentials that are different from your email account. Usually, everyone uses the same username and password as your email address to log in to your mail server. The “SMTP error 535 authentication failed” message may occur if you mistakenly enter the wrong username or password into your program. Some of the common reasons for SMTP error 535 authentication failed message are: In some cases, the server may not display any error messages. The server shows different error messages depending on the email program.

If any inappropriate authentication is detected by the server, an error message is generated. To send the messages, the mail client uses Simple Mail Transfer Protocol (SMTP). Causes for “SMTP Error 535 Authentication Failed” Message

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. If your mail server rejects the credentials you entered to the field of username or password, it will result in authentication failure.Īs a server management service provider, our technical support team gets a lot of queries to fix authentication failure errors.

Generally, the error occurs when you fail to log in with the wrong user or password.

It is more often to find an error of authentication failure on your server when you try to log in.

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