What is smtp error in mail

SMTP (Simple Mail Transfer Protocol) errors occur when there is a problem with the transmission of an email message between the sender's email server and the recipient's email server. Here are some common SMTP errors:

1. SMTP 421: Connection timed out: The connection between the sender's email server and the recipient's email server timed out, and the email was not delivered.
2. SMTP 450: Requested action not taken: The recipient's email server is unable to accept the email due to a temporary issue, such as a full mailbox or a problem with the recipient's email account.
3. SMTP 451: Requested action aborted: local error in processing: The recipient's email server is unable to accept the email due to a local error, such as a problem with the email server's configuration.
4. SMTP 452: Requested action not taken: insufficient storage: The recipient's email server is unable to accept the email due to a lack of storage space.
5. SMTP 550: Requested action not taken: mailbox unavailable: The recipient's email account is not available, or the mailbox is full.
6. SMTP 551: User not local: The recipient's email account is not recognized by the recipient's email server.
7. SMTP 552: Exceeded storage allocation: The recipient's email account has exceeded its storage allocation.
8. SMTP 553: Bad sequence of commands: The email client or server sent an invalid command sequence.
9. SMTP 554: Transaction failed: The email transaction failed due to a problem with the email server or the recipient's email account.
10. SMTP 555: Invalid command: The email client or server sent an invalid command.
11. SMTP 556: Mailbox is not local: The recipient's email account is not local to the recipient's email server.
12. SMTP 557: User is not authenticated: The recipient's email account is not authenticated.
13. SMTP 558: Authentication failed: The authentication process failed.
14. SMTP 559: Not supported: The requested action is not supported by the recipient's email server.
15. SMTP 561: User has moved: The recipient's email account has been moved to a different location.

These errors can occur due to various reasons such as:

• Network connectivity issues
• Email server configuration problems
• Recipient's email account issues
• Spam filters or firewalls blocking the email
• Email client or server software issues

To troubleshoot SMTP errors, you can try the following:

• Check the email client or server logs for more information about the error
• Verify the email server configuration and settings
• Check the recipient's email account status and availability
• Try sending the email again after a short period of time
• Contact the email server administrator or the recipient's email provider for assistance.