Hello, I am having a minor annoyance with Mac Mail

Running OSX Lion and Mail 5.2.

I have recently set up mail to view 3 email accounts.

Two at gmail.com and one at email.com

Every so often a message box appears
"Enter password for account"

Enter password for user "rich" on SMTP server

I do not recall setting up any account called "rich"

I have been Mail > preference > account
and there is no account set to the name "rich" only the 3 accounts I have set up and also iCloud.

I have looked at Keychain, I cannot see a name "Rich"
BUT Ii do not want to alter anything within Keychain as I am not sure of what I could be doing.

Any suggestions how this message be stopped.

Thank you