Error 421 Smtp Service Not Available
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reply codesSometimes your SMTP server may return a particular error message. The problem is that it will generally be very cryptic, like "550 Requested action not taken: mailbox unavailable" or "421 Try again later". What does these smtp error 421 4.3.2 service not available numbers mean?First of all: not any reply code is an error. Sometimes it's just smtp transient error 421 service not available a response containing a detail about the server or an answer to a command. Secondly: any code consist of three digits, and
Smtp Transient Error 421 Service Not Available Ora-06512
each conveys a particular information. The first one defines whether the server has accepted the command, fulfilled an action, run into a temporary issue, encountered an error etc; the second and the third one refine the
Ora-29278 Smtp Transient Error 421 Service Not Available
description further, stating if there's been a syntactic problem, or a connection trouble etc.Unfortunately, different servers sometimes use these codes in a different way, making the whole thing even more complicated... Anyhow, the most critical series of error messages is the 5xx one, and especially the ones from 550 to 559. In particular, you will probably get a lot of 550 SMTP error codes – that is, a problem that concerns the ora-29278 smtp transient error 421 service not available utl_smtp recipient's email address.Finally, remember that it's much easier to deal with these error codes if you choose to rely on a professional SMTP server that will help you solve any issue. turboSMTP, for instance, comes with a 24/7 customer support: you can try it free and forget once for all these issues.And here's a list of the main SMTP error or reply messages, with an explanation and a tip about what to do. CODEMEANINGHOW TO SOLVE IT / WHAT TO DO101The server is unable to connect.Try to change the server's name (maybe it was spelt incorrectly) or the connection port.111Connection refused or inability to open an SMTP stream.This error normally refers to a connection issue with the remote SMTP server, depending on firewalls or misspelled domains. Double-check all the configurations and in case ask your provider.211System status message or help reply.It comes with more information about the server.214A response to the HELP command.It contains information about your particular server, normally pointing to a FAQ page.220The server is ready.It's just a welcome message. Just read it and be happy that everything is working (so far)!221The server is closing its transmission channel. It can come with side messages like "Goodbye" or "Closing connection".The mailing session is going to end, which simply means that all messages ha
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421 Smtp Service Is Temporarily Unavailable
by: Exchange Mail transmission error: 421 Service not available,closing transmission smtp error 421 channel Previous Versions of Exchange > Exchange Previous Versions - Mail Flow and Secure Messaging smtp 421 service not available Question 0 Sign in to vote Hi, We are running Exchange 2007 SP3 We have 2 MX records for our organisation, hosted with our ISP http://www.serversmtp.com/en/smtp-error e.g. MX 10 mail.company.com.au MX 20 mail.isp.net Primary mail comes directly into our Exchange (through a Trend Smarthost). Secondary mail is forwarded from our ISP mail server. We installed updates on our Exchange 2007 server last month on 01/03/12 Since this date, we have been unable to receive mail from https://social.technet.microsoft.com/Forums/en-US/f8db70af-0549-4070-bace-1fb8c77fddf4/exchange-mail-transmission-error-421-service-not-availableclosing-transmission-channel?forum=exchangesvrsecuremessaginglegacy mail.isp.net, with the following error logged on the ISP mail server: “delivery temporarily suspended: host mail.company.com.au [IP address] refused to talk to me: 421 Service not available,closing transmission channel” We have an example of an NDR being returned several days later to sender: Subject: Undelivered Mail Returned to Sender This is the Postfix program at host mail.isp.net. I'm sorry to have to inform you that your message could not be be delivered to one or more recipients. It's attached below. For further assistance, please send mail to
By Anne P. Mitchell, CEO - January 25, 2010 30 Summary: Anybody who sends email has seen them, in one form or another - those SMTP error codes, http://www.gettingemaildelivered.com/what-those-smtp-error-codes-mean-and-why-you-should-care often returned in bounced email, such as "550 Requested action not taken: mailbox unavailable" or "550 5 2 1 mail from refused spam site." These are often in response to SMTP commands that have 'gone wrong' between your email server that sent the email, and the receiving email server that is unable to deliver it (or refuses to deliver it) for some reason. But what exactly do error 421 they mean? And why should you care? ('SMTP' stands for Simple Mail Transfer Protocol.) First, here is a list of SMTP messages and error messages, and what each message is supposed to say and mean Follow Us!Anybody who sends email has seen them, in one form or another - those SMTP error codes, often returned in bounced email, such as "550 Requested action not service not available taken: mailbox unavailable" or "550 5 2 1 mail from refused spam site." These are often in response to SMTP commands that have ‘gone wrong' between your email server that sent the email, and the receiving email server that is unable to deliver it (or refuses to deliver it) for some reason. But what exactly do they mean? And why should you care? (‘SMTP' stands for Simple Mail Transfer Protocol.) First, here is a list of SMTP codes and error codes, and what each message is supposed to say and mean: 211 - A system status message. 214 - A help message for a human reader follows. 220 - SMTP Service ready. 221 - Service closing. 250 - Requested action taken and completed. 251 - The recipient is not local to the server, but the server will accept and forward the message. 252 - The recipient cannot be VRFYed, but the server accepts the message and attempts delivery. 354 - Start message input and end with .. This indicates that the server is ready to accept the message itself
421 - The service is not available and the connection will be closed. 450 - The requested command faibe down. Please try the request again. Your cache administrator is webmaster. Generated Mon, 10 Oct 2016 02:02:14 GMT by s_wx1131 (squid/3.5.20)