[DNSB]

Originally Posted by jaslerx

I'm getting a similar result, failing to send email. I'm using a gmx account and have smtp enabled in their security settings. I also have added an exception for calibre & calibre_parallel in my antivirus and firewall.

This is the log:
AUTH LOGIN PLAIN
SIZE 69920427
STARTTLS
send: AUTH
reply: '530 Must issue a STARTTLS command first\r\n'
reply: retcode (530); Msg: Must issue a STARTTLS command first

Any ideas?

Given the STARTTLS line, have you enabled TLS in the setting for your email server in calibre? I have TLS selected in the encryption and seems to be working just fine. I've attached an screencap of the setup I am using.

Edit: added the debug log from a successful send from my system:

Spoiler:

Starting job: Email 12 34567890 ABCDEF1 to xxxxyyyyzzz@washout.ca	connect: (u'mail.gmx.com', 587) 
	connect: (u'mail.gmx.com', 587) 
	reply: '220 gmx.com (mrgmx003) Nemesis ESMTP Service ready\r\n' 
	reply: retcode (220); Msg: gmx.com (mrgmx003) Nemesis ESMTP Service ready 
	connect: gmx.com (mrgmx003) Nemesis ESMTP Service ready 
	send: 'ehlo [192.168.38.1]\r\n' 
	reply: '250-gmx.com Hello [192.168.38.1] [96.49.89.44]\r\n' 
	reply: '250-8BITMIME\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 [192.168.38.1] [96.49.89.44]
	8BITMIME
	AUTH LOGIN PLAIN
	SIZE 69920427
	STARTTLS 
	send: 'STARTTLS\r\n' 
	reply: '220 OK\r\n' 
	reply: retcode (220); Msg: OK 
	send: 'ehlo [192.168.38.1]\r\n' 
	reply: '250-gmx.com Hello [192.168.38.1] [96.49.89.44]\r\n' 
	reply: '250-8BITMIME\r\n' 
	reply: '250-AUTH LOGIN PLAIN\r\n' 
	reply: '250 SIZE 69920427\r\n' 
	reply: retcode (250); Msg: gmx.com Hello [192.168.38.1] [96.49.89.44]
	8BITMIME
	AUTH LOGIN PLAIN
	SIZE 69920427 
	send: AUTH <censored> 
	reply: '235 Authentication succeeded\r\n' 
	reply: retcode (235); Msg: Authentication succeeded 
	send: u'mail FROM:<xxxxyyyyzzz@gmx.com> size=1088476\r\n' 
	reply: '250 Requested mail action okay, completed\r\n' 
	reply: retcode (250); Msg: Requested mail action okay, completed 
	send: u'rcpt TO:<xxxxyyyyzzz@washout.ca>\r\n' 
	reply: '250 OK\r\n' 
	reply: retcode (250); Msg: OK 
	send: 'data\r\n' 
	reply: '354 Start mail input; end with <CRLF>.<CRLF>\r\n' 
	reply: retcode (354); Msg: Start mail input; end with <CRLF>.<CRLF> 
	data: (354, 'Start mail input; end with <CRLF>.<CRLF>') 
	send: 'Content-Type: multipart/mixed; boundary="===============0803863480=="\r\nMIME-Version: 1.0\r\nSubje... 
	reply: '250 Requested mail action okay, completed: id=0LmKag-1h5R8W1OHC-00Zx7z\r\n' 
	reply: retcode (250); Msg: Requested mail action okay, completed: id=0LmKag-1h5R8W1OHC-00Zx7z 
	data: (250, 'Requested mail action okay, completed: id=0LmKag-1h5R8W1OHC-00Zx7z') 
	send: 'quit\r\n' 
	reply: '221 gmx.com Service closing transmission channel\r\n' 
	reply: retcode (221); Msg: gmx.com Service closing transmission channel 
	Email successfully sent