How do I fix SMTP Error 421?

To fix the error 421, follow the given solutions:

  1. Modify SMTP Settings. By default, the SMTP uses port 25.
  2. Remove and Re-add Email Account.
  3. Disable Firewall.
  4. Check Other Applications.
  5. Repair PST File to Fix 421 Cannot Connect to SMTP.

What is Rcpt command in SMTP?

The RCPT TO command specifies the recipient. As an argument, RCPT TO includes a destination mailbox (forward-path). In case of multiple recipients, RCPT TO will be used to specify each recipient separately.

What is a 421 email error?

A 421 email error is typically a temporary routing issue on the receiving mail server’s end. These should usually be resolved automatically, and you should receive a final bounce-back message if the message completely fails. You usually would not receive a bounce-back message for this type of error.

What are SMTP codes?

An SMTP response code consists of three digits:

  • The error code class: This first digit indicates whether or not the server accepted the command.
  • Subject: The second digit in the SMTP response code gives you more information, stating whether there was a syntactic problem, connection trouble, or something else.

How do I fix SMTP Error in Outlook?

Fix SMTP Server error in Email

  1. Open your email client program (Outlook Express, Outlook, Eudora or Windows Mail)
  2. Click “Accounts” in the “Tools” menu.
  3. Click on your email account then click “Properties” button.
  4. Click “General” tab.
  5. Ensure that the “E-mail address” is your valid address for this account.
  6. Click “Servers” tab.

What is the first command sent to a SMTP server?

Each command is used in a normal communication sequence between two servers through the SMTP protocol, in order to deliver emails. It’s the first SMTP command: is starts the conversation identifying the sender server and is generally followed by its domain name.

Which of the following are SMTP commands?

SMTP commands

Subcommand Supported by SMTP Server Description
DATA YES Defines information as the data text of the mail body.
EHLO NO Identifies the domain name of the sending host to SMTP.
EXPN YES Verifies whether a mailbox exists on the local host.
HELO YES Identifies the domain name of the sending host to SMTP.

How do I find my SMTP error?

To verify your existing SMTP server settings:

  1. Open your email client program (Outlook Express, Outlook, Eudora or Windows Mail)
  2. Click “Accounts” in the “Tools” menu.
  3. Click on your email account then click “Properties” button.
  4. Click “General” tab.
  5. Ensure that the “E-mail address” is your valid address for this account.

What is a SMTP error?

An SMTP response code is a three digit code that the servers use to communicate throughout the email sending process. If there is a communication error, you will receive an SMTP error code — a message that indicates the specific problem; like the end of server communication which is error code 550 (The request failed).

How do you fix SMTP connect () failed?

How to fix SMTP Error: Failed to connect to server

  1. Modify the firewall rules on the server to allow outbound connections on ports like 465.
  2. Modify the SMTP restrictions on the server.
  3. Edit PHPMailer settings like Host, Port etc.
  4. Correct DNS resolution for mail server.

What does the code 334 mean in SMTP?

334 – Provide SMTP authentication credentials. 4 means the server is facing a temporary failure but the command could still be completed if tried again. Codes beginning with 4 are typically errors related to the receiving mail system. Note: Response codes beginning with 4 and 5 indicate an error has occurred.

What does SMTP error 421 mean in error code?

The SMTP error 421 is normally used for temporary problems on the mail server or a problem with the recipients email account. Some mail providers might also return 421 after you reached a limit (restriction) on your mail account (see SMTP Error 451 below). SMTP Error 451 451 4.3.0 Mail server temporarily rejected message

What does the SMTP response code 471 mean?

SMTP response codes Code What it means 471 Mail server error due to the local spam 500 Syntax error (also a command line may be 501 Syntax error in parameters or arguments 502 The server has not implemented the comma

What does the response code for SMTP mean?

SMTP response codes Code What it means 101 Server connection error (wrong server na 211 System status (response to HELP) 214 Help message (response to HELP) 220 The server is ready (response to the cli