still I think all 3 self.rset()'s in SMTP.sendmail, which are followed by a raise <someerror> statement have to be bracketed with an except clause or so - nowadays better like """
try: self.res()
except (EnvironmentError, SMTPException):
    pass
""",  as all socket.error, sslerror seem meanwhile correctly inherited (via IOError).

Because the original error must pop up, not a side effect of state cleaning!