I have a really serious problem with outlook and I'm out of my wits and can't seem to fix it. Please read the entire post carefully before posting any suggestions or jumping to conclusions.
The problem is that for one of my pop3 accounts, outgoing mails stopped working one fine day and gave the error message:
Sending reported error(0x800CCC78): 'Unable to send the message. Please verify the e-mail address in your account properties. The server responded:550 206.91.xxx.xxx is blacklisted.'
Now, my pop server that I'm connecting to requires SMTP authentication, else the server will return the above message error 550. Here is what I've tried:
- The same account works fine with Mozilla Thunderbird and outgoing is just fine.
- I've tried deleting and recreating the account in outlook
- Upgraded Outlook2003 to SP3
- Tried switches like outlook.exe /cleanprofile
After a lot of troubleshooting, I decided to use a packet analyzer to see what the problem is. Here is what I found:
Outlook is simply failing to logon to SMTP server before attempting to send a mail using RCPT command although the option to logon to SMTP server with same settings as incoming server is checked. While Thunderbird is using the AUTH PLAIN login command and is able to successfully authenticate on the SMTP server, outlook is simply failing to send the AUTH PLAIN or AUTH LOGIN command.
I've checked the registry keys and even there the SMTP server login key is set to 1. Disabling it and re-enabling also doesn't help. I've tried recreating the account several times in outlook and it still fails to send the AUTH command to logon to SMTP server before attempting to send an email.
My question here is, is there a way I could completely remove the account from Outlook cache or some place where outlook treats this as a new account. I have other accounts in Outlook for which the SMTP logon before sending mail is happening just fine. It is a problem in outlook with just this 1 account. I suspect a cache of the account settings stored somewhere is being repeatedly used.
I've done flushdns to make sure that the computer is not sticking to the same outgoing server name/ip
Somebody please help!!