[DNSB]

Originally Posted by yourservant

My new (used) Paperwhite works great! I have downloaded books from the Kindle and I have transferred documents using the Amazon "Manage Your Content and Devices" page.

I used calibre to download several news files (MOBI format) onto my PC, running Windows 10. They read fine on my PC monitor. However, I have been unsuccessful in getting anything to transfer from calibre to the Kindle device. Even my test email gives me an error:

Spoiler:

Traceback (most recent call last):
File "site-packages\calibre\gui2\wizard\send_email.py", line 207, in test_email_settings
File "site-packages\calibre\utils\smtp.py", line 158, in sendmail
File "site-packages\calibre\utils\smtplib.py", line 648, in login
SMTPAuthenticationError: (535, 'Authentication credentials invalid')


[SIZE="5"][SIZE="4"]Log:
connect: (u'mail.gmx.com', 587)
connect: (u'mail.gmx.com', 587)
reply: '220 gmx.com (mrgmx101) Nemesis ESMTP Service ready\r\n'
reply: retcode (220); Msg: gmx.com (mrgmx101) Nemesis ESMTP Service ready
connect: gmx.com (mrgmx101) Nemesis ESMTP Service ready
send: 'ehlo Jim-work-PC.Belkin\r\n'
reply: '250-gmx.com Hello Jim-work-PC.Belkin [73.235.205.107]\r\n'
reply: '250-AUTH LOGIN PLAIN\r\n'
reply: '250-SIZE 69920427\r\n'
reply: '250 STARTTLS\r\n'
reply: retcode (250); Msg: gmx.com Hello Jim-work-PC.Belkin [73.235.205.107]
AUTH LOGIN PLAIN
SIZE 69920427
STARTTLS
send: 'STARTTLS\r\n'
reply: '220 OK\r\n'
reply: retcode (220); Msg: OK
send: 'ehlo Jim-work-PC.Belkin\r\n'
reply: '250-gmx.com Hello Jim-work-PC.Belkin [73.235.205.107]\r\n'
reply: '250-AUTH LOGIN PLAIN\r\n'
reply: '250 SIZE 69920427\r\n'
reply: retcode (250); Msg: gmx.com Hello Jim-work-PC.Belkin [73.235.205.107]
AUTH LOGIN PLAIN
SIZE 69920427
send: 'AUTH PLAIN AEBnbXguY29tAFNlc2FtZTEh\r\n'
reply: '535 Authentication credentials invalid\r\n'
reply: retcode (535); Msg: Authentication credentials invalid

Initially I tried sending from my gmail address. I tried "less secure app access" and also tried using my new gmx.com email. Nothing seems to work for me here!

Any suggestions?

Looking at your posted log, you appear to be using incorrect credentials for your connection to the server.

Edit: One quick question, did you login to GMX using a web browser, click settings at the bottom of the email tab, select POP3 & IMAP and check the box that says allow access to this account via POP3 and IMAP? I did some quick checking and if that access is not enabled, I got the authentication failure error.