[gbm]

Under formats the only format listed should be epub.

I also recommend using GMX as a email relay.
From the calibre FAQ

Note

Microsoft/GMX can disable your account if you use it to send large amounts of email. So, when using these services to send mail calibre automatically restricts itself to sending one book every five minutes. If you don’t mind risking your account being blocked you can reduce this wait interval by going to Preferences → Advanced → Tweaks in calibre.

https://manual.calibre-ebook.com/faq...-using-calibre

From your prior posts you have this setting set to 1 second, please note that Amazon will ban you for an unknown period of time if you use this setting to much, I recommending setting it back to fime minutes.

This is what a successful email using GMX for a relay should look like.

Spoiler:

Starting job: Email Time Reavers to ****************@kindle.com 
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 [127.0.1.1]\r\n' 
reply: b'250-gmx.net Hello [127.0.1.1] [173.***.***.***]\r\n' 
reply: b'250-8BITMIME\r\n' 
reply: b'250-SIZE 141557760\r\n' 
reply: b'250 STARTTLS\r\n' 
reply: retcode (250); Msg: b'gmx.net Hello [127.0.1.1] [173.***.***.***]\n8BITMIME\nSIZE 141557760\nSTARTTLS' 
send: 'STARTTLS\r\n' 
reply: b'220 OK\r\n' 
reply: retcode (220); Msg: b'OK' 
send: 'ehlo [127.0.1.1]\r\n' 
reply: b'250-gmx.net Hello [127.0.1.1] [173.***.***.***]\r\n' 
reply: b'250-8BITMIME\r\n' 
reply: b'250-AUTH LOGIN PLAIN\r\n' 
reply: b'250 SIZE 141557760\r\n' 
reply: retcode (250); Msg: b'gmx.net Hello [127.0.1.1] [173.***.***.***]\n8BITMIME\nAUTH LOGIN PLAIN\nSIZE 141557760' 
send: AUTH  
reply: b'235 Authentication succeeded\r\n' 
reply: retcode (235); Msg: b'Authentication succeeded' 
send: 'mail FROM: size=2350976\r\n' 
reply: b'250 Requested mail action okay, completed\r\n' 
reply: retcode (250); Msg: b'Requested mail action okay, completed' 
send: 'rcpt TO:\r\n' 
reply: b'250 OK\r\n' 
reply: retcode (250); Msg: b'OK' 
send: 'data\r\n' 
reply: b'354 Start mail input; end with .\r\n' 
reply: retcode (354); Msg: b'Start mail input; end with .' 
data: (354, b'Start mail input; end with .') 
send: b'From: xxxxxxxxxx@gmx.com\r\nTo: ****************@kindle.com\r\nSubject: iGi6JqpSdeMoRCUe4kxjYE\r\nD... 
reply: b'250 Requested mail action okay, completed: id=1Ma20k-1srz1L0hS0-00Oky4\r\n' 
reply: retcode (250); Msg: b'Requested mail action okay, completed: id=1Ma20k-1srz1L0hS0-00Oky4' 
data: (250, b'Requested mail action okay, completed: id=1Ma20k-1srz1L0hS0-00Oky4') 
send: 'quit\r\n' 
reply: b'221 gmx.net Service closing transmission channel\r\n' 
reply: retcode (221); Msg: b'gmx.net Service closing transmission channel' 
Email successfully sent

bernie

Originally Posted by Tipiford

Settings screenshot