Authentication is denied, even if login successful

[JM-Lemmi]

A simple Testmail to one recipient works, but a longer mail to multiple recipient fails. Needs more investigation

Apr 08 13:02:41 xxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxx python/send_mail.py: send_mail started!
Apr 08 13:02:41 xxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxx python/send_mail.py: Successfully authenticated.
Apr 08 13:02:41 xxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxx python/__init__.py: Ihre Mail wurde gesendet.
Apr 08 13:02:41 xxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxx python/send_mail.py: Payload sent: result=Response(success=True, message='Ihre Mail wurde gesendet.')
Apr 08 13:02:41 xxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxx python/send_mail.py: Bounce sent: result=Response(success=True, message='Ihre Mail wurde gesendet.')
Apr 08 13:02:41 xxxxxxxxxx postfix/pipe[64521]: 0AE2F3FDB3: to=<xxxxxxx@student.dhbw-mannheim.de>, relay=zimbrawebtransport, delay=0.6, delays=0.01/0/0/0.59, dsn=2.0.0, status=sent (delivered via zimbrawebtransport service)
Apr 08 13:02:41 xxxxxxxxxx postfix/qmgr[97]: 0AE2F3FDB3: removed
Apr 08 13:02:42 xxxxxxxxxx postfix/submission/smtpd[64504]: disconnect from unknown[141.72.132.153] ehlo=2 starttls=1 auth=1 mail=2 rcpt=2 data=2 quit=1 commands=11
Apr 08 13:03:59 xxxxxxxxxx postfix/submission/smtpd[64504]: connect from unknown[141.72.132.153]
Apr 08 13:03:59 xxxxxxxxxx postfix/submission/smtpd[64504]: Anonymous TLS connection established from unknown[141.72.132.153]: TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)
Apr 08 13:04:00 xxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxx python/zimbra_authentication.py: Trying to authenticate user AUTH_USERNAME='xxxxxxx'
Apr 08 13:04:00 xxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxx python/zimbra_authentication.py: successfully authenticated AUTH_USERNAME='xxxxxxx'
Apr 08 13:04:02 xxxxxxxxxx postfix/submission/smtpd[64504]: warning: unknown[141.72.132.153]: SASL LOGIN authentication failed: UGFzc3dvcmQ6
Apr 08 13:04:02 xxxxxxxxxx postfix/submission/smtpd[64504]: lost connection after AUTH from unknown[141.72.132.153]
Apr 08 13:04:02 xxxxxxxxxx postfix/submission/smtpd[64504]: disconnect from unknown[141.72.132.153] ehlo=2 starttls=1 auth=0/1 commands=3/4
Apr 08 13:04:09 xxxxxxxxxx postfix/submission/smtpd[64504]: connect from unknown[141.72.132.153]
Apr 08 13:04:09 xxxxxxxxxx postfix/submission/smtpd[64504]: Anonymous TLS connection established from unknown[141.72.132.153]: TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)
Apr 08 13:04:13 xxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxx python/zimbra_authentication.py: Trying to authenticate user AUTH_USERNAME='xxxxxxx'
Apr 08 13:04:14 xxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxx python/zimbra_authentication.py: successfully authenticated AUTH_USERNAME='xxxxxxx'
Apr 08 13:04:16 xxxxxxxxxx postfix/submission/smtpd[64504]: warning: unknown[141.72.132.153]: SASL LOGIN authentication failed: UGFzc3dvcmQ6
Apr 08 13:04:16 xxxxxxxxxx postfix/submission/smtpd[64504]: lost connection after AUTH from unknown[141.72.132.153]
Apr 08 13:04:16 xxxxxxxxxx postfix/submission/smtpd[64504]: disconnect from unknown[141.72.132.153] ehlo=2 starttls=1 auth=0/1 commands=3/4
Apr 08 13:05:24 xxxxxxxxxx postfix/submission/smtpd[64504]: connect from unknown[141.72.132.153]
Apr 08 13:05:24 xxxxxxxxxx postfix/submission/smtpd[64504]: Anonymous TLS connection established from unknown[141.72.132.153]: TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)
Apr 08 13:05:24 xxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxx python/zimbra_authentication.py: Trying to authenticate user AUTH_USERNAME='xxxxxxx'
Apr 08 13:05:24 xxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxx python/zimbra_authentication.py: successfully authenticated AUTH_USERNAME='xxxxxxx'
Apr 08 13:05:26 xxxxxxxxxx postfix/submission/smtpd[64504]: warning: unknown[141.72.132.153]: SASL LOGIN authentication failed: UGFzc3dvcmQ6
Apr 08 13:05:26 xxxxxxxxxx postfix/submission/smtpd[64504]: lost connection after AUTH from unknown[141.72.132.153]
Apr 08 13:05:26 xxxxxxxxxx postfix/submission/smtpd[64504]: disconnect from unknown[141.72.132.153] ehlo=2 starttls=1 auth=0/1 commands=3/4

[JM-Lemmi]

Maybe Fehlalarm?

After enough tries it worked:

Apr 08 13:14:47 xxxxxxxxxxxxxxxxxxxxxxxxx python/zimbra_authentication.py: Trying to authenticate user AUTH_USERNAME='xxxxxxx'
Apr 08 13:14:47 xxxxxxxxxxxxxxxxxxxxxxxxx python/zimbra_authentication.py: successfully authenticated AUTH_USERNAME='xxxxxxx'
Apr 08 13:14:47 xxxxxxxxxxxxxxxxxxxxxxxxx python/zimbra_milter.py: user xxxxxxx sent mail from <xxxxxxx@student.dhbw-mannheim.de>
Apr 08 13:14:47 xxxxxxxxxx postfix/submission/smtpd[64543]: DE8A53E60B: client=unknown[141.72.132.153], sasl_method=LOGIN, sasl_username=xxxxxxx
Apr 08 13:14:47 xxxxxxxxxx postfix/cleanup[64551]: DE8A53E60B: message-id=<006b01d84b4a$824a2530$86de6f90$@student.dhbw-mannheim.de>
Apr 08 13:14:47 xxxxxxxxxx postfix/qmgr[97]: DE8A53E60B: from=<xxxxxxx@student.dhbw-mannheim.de>, size=1770, nrcpt=5 (queue active)
Apr 08 13:14:48 xxxxxxxxxxxxxxxxxxxxxxxxx python/send_mail.py: send_mail started!
Apr 08 13:14:48 xxxxxxxxxxxxxxxxxxxxxxxxx python/send_mail.py: Successfully authenticated.
Apr 08 13:14:48 xxxxxxxxxxxxxxxxxxxxxxxxx python/send_mail.py: send_mail started!
Apr 08 13:14:48 xxxxxxxxxxxxxxxxxxxxxxxxx python/send_mail.py: User s211266 tried to send email claiming to be "Julian Lemmerich" <xxxxxxx@student.dhbw-mannheim.de>
Apr 08 13:14:48 xxxxxxxxxxxxxxxxxxxxxxxxx python/send_mail.py: send_mail started!
Apr 08 13:14:48 xxxxxxxxxxxxxxxxxxxxxxxxx python/send_mail.py: Successfully authenticated.
Apr 08 13:14:48 xxxxxxxxxx postfix/pipe[64555]: DE8A53E60B: to=<xxxxxxx@student.dhbw-mannheim.de>, relay=zimbrawebtransport, delay=1.1, delays=0.1/0.04/0/0.92, dsn=2.0.0, status=sent (delivered via zimbrawebtransport service)
Apr 08 13:14:48 xxxxxxxxxx postfix/pipe[64555]: DE8A53E60B: to=<xxxxxxx@student.dhbw-mannheim.de>, relay=zimbrawebtransport, delay=1.1, delays=0.1/0.04/0/0.92, dsn=2.0.0, status=sent (delivered via zimbrawebtransport service)
Apr 08 13:14:48 xxxxxxxxxx postfix/pipe[64555]: DE8A53E60B: to=<xxxxxxx@student.dhbw-mannheim.de>, relay=zimbrawebtransport, delay=1.1, delays=0.1/0.04/0/0.92, dsn=2.0.0, status=sent (delivered via zimbrawebtransport service)
Apr 08 13:14:49 xxxxxxxxxxxxxxxxxxxxxxxxx python/__init__.py: Ihre Mail wurde gesendet.
Apr 08 13:14:49 xxxxxxxxxxxxxxxxxxxxxxxxx python/send_mail.py: Sent mail, result=Response(success=True, message='Ihre Mail wurde gesendet.')
Apr 08 13:14:49 xxxxxxxxxxxxxxxxxxxxxxxxx python/__init__.py: Ihre Mail wurde gesendet.
Apr 08 13:14:49 xxxxxxxxxxxxxxxxxxxxxxxxx python/send_mail.py: Sent mail, result=Response(success=True, message='Ihre Mail wurde gesendet.')
Apr 08 13:14:49 xxxxxxxxxx postfix/pipe[64552]: DE8A53E60B: to=<service@dhbw-mannheim.de>, relay=zimbrawebtransport, delay=1.4, delays=0.1/0.01/0/1.3, dsn=2.0.0, status=sent (delivered via zimbrawebtransport service)
Apr 08 13:14:49 xxxxxxxxxx postfix/pipe[64553]: DE8A53E60B: to=<xxxxxxxx@gmx.de>, relay=zimbrawebtransport, delay=1.4, delays=0.1/0.03/0/1.3, dsn=2.0.0, status=sent (delivered via zimbrawebtransport service)
Apr 08 13:14:49 xxxxxxxxxx postfix/qmgr[97]: DE8A53E60B: removed
Apr 08 13:14:50 xxxxxxxxxx postfix/submission/smtpd[64543]: disconnect from unknown[141.72.132.153] ehlo=2 starttls=1 auth=1 mail=1 rcpt=5 data=1 quit=1 commands=12