Thanks for the email and screen shots. I am thinking some new questions, and possible answers may result.
First, can you show me what the choices would be for SMTP Relay Personality -- I am not sure they matter with the SMTP of the ISP, but I am unfamiliar with what Eudora might offer, in that section.
Secondly, and perhaps more importantly, is the full meaning of the choice to
Allow Authentication in Eudora versus choices available when editing the Mail Preferences. I think the Login ID you show in the screenshots is that used for your Domain -- is that correct? Is that same Login ID used when authenticating the Incoming server with PaulBunyan? If different, and if Mail attempted to use the Login ID entered as the Username when authenticating the SMTP, then there could be a problem.
Hitherto-fore the choices in Mail for authenticating the SMTP have seemed to me to be either None or Password (or other form of authentication). Recently, when setting up a new account in Tiger, I have noticed an opportunity to check
Allow Authentication but not enter any Username or Password. With my provider this turned out to be the same as None, but it might not be with all SMTP providers. When only editing the preferences, I still cannot find the exact equivalent, if there is a difference.
If, on your Mac, the messages in Inboxes could be moved to other, On My Mac mailboxes, you could remove the accounts (maybe only need to remove the account with the ISP, but remove all SMTPs, and then add an account, which would trigger the account set up assistant, which will offer the choice to say Allow Authentication, but then enter no Username and Password when setting up the SMTP to use for Outgoing Server. Transferring any messages in the Inbox (and Sent if it were applicable) must be done before removing the account, since removal will result in the permanent loss of all messages in the mailboxes normally found in the account folder of the account being removed.
In summary, please email additional info, or comment generally about the role of the Login ID entry displayed in the screens you have already sent. If willing to remove the account with the ISP, please clarify what you understand to be needed when doing this.
Ernie