hey goodear,
Usually the email server fails when you don’t use the right address or password and that would be consistent. The inconsistent error is mostly due to a misaddressed SMTP sending port. Default is 25 but large and secure ISP’s use alternative ports and authorizations. Eathlink for example uses a SMTPAUTH.earthlink.net authorization rather than the standard SMTP.earthlink.net, they also use port 587 rather than port 25.
If you have two SMTP servers set up in your mail accounts and one fails, it will automatically seek a SMTP server that functions, this is set to default. Then it will work but the path is created and preferences altered so when you try to reengage to SMTP server again the settings are confused and the preferences need to be reestablished with a reboot.
You need to read the ISP or if your using a WEB site server, their SMTP preference data to find the right settings.
I run 6 different SMTP servers from my iBook, and each require it’s own settings. If I want to I can use my ISP (earthlink) SMTP server settings for all my outgoing mail, but I rather use the servers that the mail comes in on.
For example, Techsurvivors.net has a SMTP server that I can receive email from, I can choose to send mail out the TS SMTP server or out my earthlink server or our my website server or out my business server, each is unique and each with give you a different HEADER READING.
I hope that helps.