GMX Email Sending

[JohnJackDoe tele2 de]

GMX Email Sending

Dear list members,

I have an GMX.net email account. Retrieving email is working. Sending  
email aborts with failure 501. Here is the debugging log:
** (balsa:10386): DEBUG: balsa_send_message_real: starting
** (balsa:10386): DEBUG: connected to smtp.gmx.net:587
** (balsa:10386): DEBUG: R '220 gmx.com (mrgmx002) Nemesis ESMTP  
Service ready'
** (balsa:10386): DEBUG: W 'EHLO Netbook-11'
** (balsa:10386): DEBUG: R '250-gmx.com Hello Netbook-11 [46.142.3.151]'
** (balsa:10386): DEBUG: R '250-AUTH LOGIN PLAIN'
** (balsa:10386): DEBUG: R '250-SIZE 69920427'
** (balsa:10386): DEBUG: R '250 STARTTLS'
** (balsa:10386): DEBUG: W 'STARTTLS'
** (balsa:10386): DEBUG: R '220 OK'
** (balsa:10386): DEBUG: W 'EHLO Netbook-11'
** (balsa:10386): DEBUG: R '250-gmx.com Hello Netbook-11 [46.142.3.151]'
** (balsa:10386): DEBUG: R '250-AUTH LOGIN PLAIN'
** (balsa:10386): DEBUG: R '250 SIZE 69920427'
** (balsa:10386): DEBUG: emit 'auth' signal for client 0xa70cdc8
** (balsa:10386): DEBUG: libbalsa_server_get_auth: 0xa70cdc8 0xa01b148:  
encrypted = 1
** (balsa:10386): DEBUG: W 'AUTH PLAIN  
NDAyMTgxMjQANDAyMTgxMjQAMTlTaWdyaWQ0OA=='
** (balsa:10386): DEBUG: R '235 Authentication succeeded'
** (balsa:10386): DEBUG: balsa_send_message_real: connect = 1  
[0xa6a8060]: 'gmx.com (mrgmx002) Nemesis ESMTP Service ready'
** (balsa:10386): DEBUG: balsa_send_message_real: mqi = 0xa3b16f8
** (balsa:10386): DEBUG: W 'MAIL FROM:<xxxx xxxx gmx net> RET=HDRS  
ENVID=AS7YTTPP.PM3KQIOR.K4KZE5NR@VHL5VDJN.EOVDB43N.YHRW6TNF'
** (balsa:10386): DEBUG: R '501 Syntax error in parameters or arguments'
** (balsa:10386): DEBUG: W 'QUIT'
** (balsa:10386): DEBUG: R '221 gmx.com Service closing transmission  
channel'
** (balsa:10386): DEBUG: finalised connection to smtp.gmx.net:587

BTW: I have setup 'TLS required'. So IMHO it shouldn't be 'STARTTLS'.

Any ideas? Thank you for all your support.
--
Bet regards and Happy Easter,
John Jack Doe