aliweb

I have a simple VB application which sends mail. I am using Dundas Mailer component.
When I use my ISPs SMTP server to which I am currently connected then the mail is sent without errors.
But when I use my web hosting provider's SMTP then I get the following error.

"The RCPT command failed. The specified account does not exist."

Even though I am using User and Password authentication but I still get the same error. I used another web hosting provider's SMTP but same error.
I also used ASPEmail by Persits Software but same error. How can I rectify it?

aliweb

Anyone please!?

vb_programmer

Well , there is a little confusion. You said you are not able to use the Email address of your Web Hosting provider. Here , I have assumed that you have registered a Web Space with some Hosting Company and they provide Email address to you.

In this case ...

[1] Check if your Domain Name is active and alive.
[2] Check if the Name Servers for your Domain name (pointing towards the same Web Space) are resolved correctly.
[3] If that Email address is provided by your Hosting Company , then you must be having an alternative to log-in to this Email address. usually it's www.DomainName.tld/webmail (if you are hosting on Linux server) and see if you can log-in to your same Email account online through webmail programs like NeoMail and so on.

If
everything above turns out as true and valid then come back again here and we will think off something else then ...
Else
take necessary actions and rectify.

dilettante

RCPT is "recipient." It sounds like the web hosting outfit's post office (say, mywebhost.com) isn't forwarding mail, something every post office can choose not to handle as an administrative option. This may be done to keep customers from spamming the world, yet allow your web applications to use SMTP to deliver site feedback, etc. to your mailbox on their post office.

It could also be that you are addressing mail to an account at that post office (joe@mywebhost.com), but the account (joe) doesn't exist there. Could it be a typo someplace?

I don't think this is a client authentication error message though. It just sounds like a non-relaying mail server.

vb_programmer

But he is saying that he is able to send Emails through his ISPs Email address. So , this means that Email address to which he is trying to send Email does exist.

dilettante

Yes, I was pretty sure that was what he was saying.

My main suggestion was that perhaps the web hosting companies' SMTP servers do not relay mail. Perhaps they only accept mail for accounts on that server.

That's about the only thing I can think of that might lead to the error response on a RCPT that he is seeing. The actual SMTP error code (550, 551, etc.) might be useful in diagnosing this too. For example a 550 can mean "I don't relay" and a 551 normally means "user not local, try supplying a forward-path" though the latter is pretty obsolete.

I've written a mail server of my own that returns "550 No such user here" if you try to send non-local mail. Of course this server doesn't forward/relay mail, by design. It is meant to be an email endpoint or "delivery" server only.

If he is seeing an authentication problem I would think it would occur earlier, on the MAIL command.

Just a thought.

vb_programmer

Yes. this is true. Many of SMTPs from Web Hosting servers allow to sketch your email on the canvas of restricted Email Servers (or Domains). They think you should use the Email address on Hosting Server for Form-to-Mail or Forum-Admin programs.

Around 1 year ago , I also attempted to write a Email server. In that , I too implemented the same restriction and allowed email to only Hotmail and Yahoo accounts. For all other , it returned the same kind of error.

I don't know how much this discussion is helping aliweb ; but for me , it's really refreshing experience ! Talking to knowledgable guy like you is always a pleasure.

dilettante

I hope he gets something useful out of our discussion.

For SMTP and email issues I tend to rely on the RFCs and the web sites of some email server vendors where they discuss how loose the email specs can be and how they cope with various mail client quirks. I won't pretend to be any sort of expert, but I did spend a lot of time getting my own server working with several common clients so much of this is fairly fresh in my mind.

I agree, nice dialog. It sounds as if we've been over much of the same ground.