[cboscari]

I own a Kindle Scribe, and it seems epub and mobi files will only allow handwritten notes if they are mailed to my Kindle. OK. but when I test my setup to mail from inside Calibre, I get this -
raceback (most recent call last):
File "calibre/gui2/wizard/send_email.py", line 223, in test_email_settings
File "calibre/utils/smtp.py", line 181, in sendmail
File "smtplib.py", line 750, in login
File "smtplib.py", line 739, in login
File "smtplib.py", line 662, in auth
smtplib.SMTPAuthenticationError: (535, b'Authentication credentials invalid')


Log:
connect: to ('mail.gmx.com', 587) None
reply: b'220 gmx.net (mrgmx004) Nemesis ESMTP Service ready\r\n'
reply: retcode (220); Msg: b'gmx.net (mrgmx004) Nemesis ESMTP Service ready'
connect: b'gmx.net (mrgmx004) Nemesis ESMTP Service ready'
send: 'ehlo localhost.localdomain\r\n'
reply: b'250-gmx.net Hello localhost.localdomain [47.148.46.100]\r\n'
reply: b'250-8BITMIME\r\n'
reply: b'250-SIZE 69920427\r\n'
reply: b'250 STARTTLS\r\n'
reply: retcode (250); Msg: b'gmx.net Hello localhost.localdomain [47.148.46.100]\n8BITMIME\nSIZE 69920427\nSTARTTLS'
send: 'STARTTLS\r\n'
reply: b'220 OK\r\n'
reply: retcode (220); Msg: b'OK'
send: 'ehlo localhost.localdomain\r\n'
reply: b'250-gmx.net Hello localhost.localdomain [47.148.46.100]\r\n'
reply: b'250-8BITMIME\r\n'
reply: b'250-AUTH LOGIN PLAIN\r\n'
reply: b'250 SIZE 69920427\r\n'
reply: retcode (250); Msg: b'gmx.net Hello localhost.localdomain [47.148.46.100]\n8BITMIME\nAUTH LOGIN PLAIN\nSIZE 69920427'
send: AUTH <censored>
reply: b'535 Authentication credentials invalid\r\n'
reply: retcode (535); Msg: b'Authentication credentials invalid'
send: AUTH <censored>
reply: b'334 UGFzc3dvcmQ6\r\n'
reply: retcode (334); Msg: b'UGFzc3dvcmQ6'
send: 'RHJ1bWJhbmQ2OTA=\r\n'
reply: b'535 Authentication credentials invalid\r\n'
reply: retcode (535); Msg: b'Authentication credentials invalid'

This is from a gmx account. I have verified that the id is the complete email address ("EliteTrickster@gmx.us") and the password is correct. I can email my regular email account from within the gmx account. Any ideas on what this might be? Thanks for any help you can give me.
Chris