We just got a server from VDI and are having some trouble sending email via SMTP. We understand and have checked our POP3 email many times but we still get this error:

An unknown error has occurred. Subject '', Account: 'mail.domain.com', Server: 'mail.domain.com', Protocol: SMTP, Port: 25, Secure(SSL): No, Error Number: 0x800CCC0B

Anybody know what the problem is?

It doesnt sound like a error message sendmail would put out or any mail program for that manner. But im not a tech so I would no. Could be a dns problem check over that carefully, that can always cause wierd errors.

Also you should no that this kind of question would be best suited for the technical forum, just a fyi...

We were also having email problems on a VDI server but a cpanel upgrade took care of that. You might want to ask VDI for a user/pass to do the upgrade.

Hello,


Apparently on some VDI boxes its no longer pop auth but where you have to send the username and password to the box , in Outlook in the account settings there is a checkbox which says.

"My Server Requires Authentication"

Check that and see if that helps.

If not, you may be on a dialup ISP which has port 25 blocked, Earthlink is in the process of adding port 25 blocking which I'm not happy about but there's nothing I can do about it except change ISP's :(

In order to be permitted to relay email thru your VDI based SMTP server, you need to follow SMTP Authentication procedures.
In order for the SMTP to authenticate your identity, and allow you send mail thru, you must first check mail via POP3, with your username and password. After that, the email software installed on the server will allow you to relay mail thru the SMTP for a period of 20-40 minutes. After that, you must once again authenticate by checking mail via POP3. Such methods are necessary to protect the servers from spammers, and to make sure only you can send mail thru your smtp servers.

Sean R.
BurstNET™
Online Rep

Add to the known Port 25 blockers:
Prodigy
UUnet (Much of their network)
...with these dial up providers, you will not be allowed to use foreign smtp relay.

Sean R.
BurstNET™
Online Rep

Or just do as my collegue mentioned, enable "Authentication on Outgoing Email"

Not all email software has those settings.
Outlook does...most others do not.
Therefore, logging in to check mail first is is the alternative.

Sean R.
BurstNET™
Online Rep

Am I correct that if they block Port 25, there isn't anything you can do? I seem to remember one ISP, which I couldn't get mail going through, even though I HAD entered the "my server requires..." and the user name and pass. Still didn't work. I think the ISP was worldspy (which is no longer).

That is exactly correct, Chicken.
This is an issue with all hosts...not just VDI.
If an ISP blocks foreign port 25 usage, you will not be able to use your own SMTP mail server no matter what.
Only way around it is if you point "smtp.yourname.com" to the IP or SMTP server of your ISP.
ie..
smtp.yourname.com = smtp.yourisp.com
Not pretty, but still better than outright usage of your ISP's mail server.

Sean R.
BurstNET™
Online Rep

If you happen to have SecureCRT you can use its nice port forwarding feature to connect to a server and forward port say 3333 to port 25 on the server. And use server requires auth and its a nice work around, works for me :D