Hello Kovid,
Thanks for your quick reply.
It may be possible i'm not understanding your suggestions, my fault. Please
allow me to repeat the situation:
I've been using Calibre for many years, and have always sent my ebooks to
Kindle using Calibre. That's why I was amazed that suddenly it stopped
working.
To make a test, I sent an ebook to Kindle using my gmail account directly
from gmail, and worked OK.
That's why I assumed there is something incorrect on Calibre side.
By "relay" do you mean setting up the GMX account mentioned inside Calibre?
Thank you again for your support!
Cordially,
Giuseppe.

Il Mar 8 Nov 2022, 00:46 Kovid Goyal <email address hidden> ha
scritto:

> Again, set up an email relay in calibre. You are sending email directly
> from your computer to amazon instead of via a relay. Amazon no longer
> allows that.
>
> --
> You received this bug notification because you are subscribed to the bug
> report.
> https://bugs.launchpad.net/bugs/1995772
>
> Title:
>   cannot email ebook to kindle
>
> Status in calibre:
>   Invalid
>
> Bug description:
>   Running Windows 11 22H2
>   Have always been able to send to kindle, recently in epub format as well
> without transforming in MOBI. This error appeared suddenly, just a day
> after successfully sending other epub books to kindle.
>
>   calibre, version 6.7.1 (win32, embedded-python: True)
>   Invio del libro tramite email non riuscito: Non riuscita: Invia tramite
> email Comunicazione Assertiva: Come Comunicare in Modo Efficace e Dare
> Inizio a Conversazioni Vincenti a <email address hidden>
>
>   Starting job: Invia tramite email Comunicazione Assertiva: Come
>   Comunicare in Modo Efficace e Dare Inizio a Conversazioni Vincenti a
>   <email address hidden>
>
>   Sending failed...
>
>   Traceback (most recent call last):
>     File "calibre\gui2\email.py", line 47, in run
>     File "calibre\gui2\email.py", line 136, in sendmail
>     File "calibre\utils\smtp.py", line 162, in sendmail
>     File "calibre\utils\smtp.py", line 142, in sendmail_direct
>   OSError: Failed to send mail: SMTPRecipientsRefused({'
> <email address hidden>': (550, b'5.7.1 IP address blacklisted by
> recipient')})
>
>
>   Job: "Invia tramite email Comunicazione Assertiva: Come Comunicare in
> Modo Efficace e Dare Inizio a Conversazioni Vincenti a
> <email address hidden>" failed with error:
>   Traceback (most recent call last):
>     File "calibre\gui2\threaded_jobs.py", line 82, in start_work
>     File "calibre\gui2\email.py", line 104, in __call__
>     File "calibre\gui2\email.py", line 47, in run
>     File "calibre\gui2\email.py", line 136, in sendmail
>     File "calibre\utils\smtp.py", line 162, in sendmail
>     File "calibre\utils\smtp.py", line 142, in sendmail_direct
>   OSError: Failed to send mail: SMTPRecipientsRefused({'
> <email address hidden>': (550, b'5.7.1 IP address blacklisted by
> recipient')})
>
>   Called with args:
> ('C:\\Users\\gnifo\\AppData\\Local\\Temp\\calibre_uf5cd_ll\\6ydlgpm8caltmpfmt.epub',
> 'Comunicazione Assertiva_ Come Comunicare in Modo Efficace e Dare Inizio a
> Conversazioni Vincenti - Donato Trebbiani.epub', '<email address hidden>',
> 'zSwrVIrfX8ELLuhh9rSRGB', 'bvcjwDUB8iBeC6zfNJs5GH') {'notifications':
> <queue.Queue object at 0x000001C3858D9900>, 'abort': <threading.Event
> object at 0x000001C3858D88E0>, 'log': <calibre.utils.logging.GUILog object
> at 0x000001C3858D8C70>}
>
> To manage notifications about this bug go to:
> https://bugs.launchpad.net/calibre/+bug/1995772/+subscriptions
>
>