SMTP 235 Authentication Successful vs 334 Server Challenge
SMTP 235 (Authentication Successful) is a 2xx Positive Completion response, while 334 (Server Challenge) is a 3xx Positive Intermediate response. 235 indicates that the client has been successfully authenticated using the AUTH command. The server will now accept mail commands from this authenticated session. In contrast, 334 means that the server is issuing an authentication challenge as part of the SASL authentication exchange. The response contains a Base64-encoded challenge that the client must decode and respond to.
Описание
The client has been successfully authenticated using the AUTH command. The server will now accept mail commands from this authenticated session.
Когда вы это видите
After submitting valid credentials via the AUTH command (LOGIN, PLAIN, or other SASL mechanism). The server has verified your identity and you can now send mail.
Как исправить
No fix needed — authentication succeeded. If you expected this but received a different code, double-check your username, password, and the authentication mechanism.
Описание
The server is issuing an authentication challenge as part of the SASL authentication exchange. The response contains a Base64-encoded challenge that the client must decode and respond to.
Когда вы это видите
During the AUTH command handshake. The server is prompting you for your username or password (Base64-encoded) as part of the multi-step authentication process.
Как исправить
Respond with the appropriate Base64-encoded credentials. If authentication keeps failing after responding, verify your credentials and ensure you are using the correct SASL mechanism.
Ключевые различия
235 is a 2xx Positive Completion response, while 334 is a 3xx Positive Intermediate response.
SMTP 235: The client has been successfully authenticated using the AUTH command. The server will now accept mail commands from this authenticated session.
SMTP 334: The server is issuing an authentication challenge as part of the SASL authentication exchange. The response contains a Base64-encoded challenge that the client must decode and respond to.
You encounter 235 when after submitting valid credentials via the AUTH command (LOGIN, PLAIN, or other SASL mechanism). The server has verified your identity and you can now send mail.
You encounter 334 when during the AUTH command handshake. The server is prompting you for your username or password (Base64-encoded) as part of the multi-step authentication process.
Когда что использовать
For 235 (Authentication Successful): No fix needed — authentication succeeded. If you expected this but received a different code, double-check your username, password, and the authentication mechanism. For 334 (Server Challenge): Respond with the appropriate Base64-encoded credentials. If authentication keeps failing after responding, verify your credentials and ensure you are using the correct SASL mechanism.