$smtp->auth( $user, $pass,'PLAIN') || die "cannot do mail auth";

##</code><code>##

 perl ./FHEM/sendEmail.pm
Net::SMTPS>>> Net::SMTPS(0.09)
Net::SMTPS>>>   IO::Socket::IP(0.39)
Net::SMTPS>>>     IO::Socket(1.39)
Net::SMTPS>>>       IO::Handle(1.39)
Net::SMTPS>>>         Exporter(5.73)
Net::SMTPS>>>   Net::SMTP(3.11)
Net::SMTPS>>>     Net::Cmd(3.11)
Net::SMTPS=GLOB(0x55ffcc1839b0)<<< 220 smtp.strato.de ESMTP RZmta (P10 -)
Net::SMTPS=GLOB(0x55ffcc1839b0)>>> EHLO localhost.localdomain
Net::SMTPS=GLOB(0x55ffcc1839b0)<<< 250-smtp.strato.de greets 89.245.1.55
Net::SMTPS=GLOB(0x55ffcc1839b0)<<< 250-ENHANCEDSTATUSCODES
Net::SMTPS=GLOB(0x55ffcc1839b0)<<< 250-PIPELINING
Net::SMTPS=GLOB(0x55ffcc1839b0)<<< 250-8BITMIME
Net::SMTPS=GLOB(0x55ffcc1839b0)<<< 250-DELIVERBY
Net::SMTPS=GLOB(0x55ffcc1839b0)<<< 250-SIZE 104857600
Net::SMTPS=GLOB(0x55ffcc1839b0)<<< 250-AUTH PLAIN LOGIN CRAM-MD5 DIGEST-MD5
Net::SMTPS=GLOB(0x55ffcc1839b0)<<< 250-STARTTLS
Net::SMTPS=GLOB(0x55ffcc1839b0)<<< 250-BURL imap
Net::SMTPS=GLOB(0x55ffcc1839b0)<<< 250-CHUNKING
Net::SMTPS=GLOB(0x55ffcc1839b0)<<< 250 HELP
Net::SMTPS=GLOB(0x55ffcc1839b0)>>> STARTTLS
Net::SMTPS=GLOB(0x55ffcc1839b0)<<< 220 Ready to start TLS
Net::SMTPS=GLOB(0x55ffcc1839b0)>>> EHLO localhost.localdomain
Net::SMTPS=GLOB(0x55ffcc1839b0)<<< 250-smtp.strato.de greets 89.245.1.55
Net::SMTPS=GLOB(0x55ffcc1839b0)<<< 250-ENHANCEDSTATUSCODES
Net::SMTPS=GLOB(0x55ffcc1839b0)<<< 250-PIPELINING
Net::SMTPS=GLOB(0x55ffcc1839b0)<<< 250-8BITMIME
Net::SMTPS=GLOB(0x55ffcc1839b0)<<< 250-DELIVERBY
Net::SMTPS=GLOB(0x55ffcc1839b0)<<< 250-SIZE 104857600
Net::SMTPS=GLOB(0x55ffcc1839b0)<<< 250-AUTH PLAIN LOGIN CRAM-MD5 DIGEST-MD5
Net::SMTPS=GLOB(0x55ffcc1839b0)<<< 250-REQUIRETLS
Net::SMTPS=GLOB(0x55ffcc1839b0)<<< 250-BURL imap
Net::SMTPS=GLOB(0x55ffcc1839b0)<<< 250-CHUNKING
Net::SMTPS=GLOB(0x55ffcc1839b0)<<< 250 HELP
Net::SMTPS=GLOB(0x55ffcc1839b0)>>> AUTH-my favorite: PLAIN
Net::SMTPS=GLOB(0x55ffcc1839b0)>>> AUTH-server offerred: PLAIN LOGIN CRAM-MD5 DIGEST-MD5
Net::SMTPS=GLOB(0x55ffcc1839b0)>>> AUTH-negotiated: PLAIN
cannot do mail auth at ./FHEM/sendEmail.pm line 18.

##</code><code>##

$smtp->auth( $user, $pass,'LOGIN') || die "cannot do mail auth";

##</code><code>##

 perl ./FHEM/sendEmail.pm
Net::SMTPS>>> Net::SMTPS(0.09)
Net::SMTPS>>>   IO::Socket::IP(0.39)
Net::SMTPS>>>     IO::Socket(1.39)
Net::SMTPS>>>       IO::Handle(1.39)
Net::SMTPS>>>         Exporter(5.73)
Net::SMTPS>>>   Net::SMTP(3.11)
Net::SMTPS>>>     Net::Cmd(3.11)
Net::SMTPS=GLOB(0x56154bf1cf60)<<< 220 smtp.strato.de ESMTP RZmta (P8 -)
Net::SMTPS=GLOB(0x56154bf1cf60)>>> EHLO localhost.localdomain
Net::SMTPS=GLOB(0x56154bf1cf60)<<< 250-smtp.strato.de greets 89.245.1.55
Net::SMTPS=GLOB(0x56154bf1cf60)<<< 250-ENHANCEDSTATUSCODES
Net::SMTPS=GLOB(0x56154bf1cf60)<<< 250-PIPELINING
Net::SMTPS=GLOB(0x56154bf1cf60)<<< 250-8BITMIME
Net::SMTPS=GLOB(0x56154bf1cf60)<<< 250-DELIVERBY
Net::SMTPS=GLOB(0x56154bf1cf60)<<< 250-SIZE 104857600
Net::SMTPS=GLOB(0x56154bf1cf60)<<< 250-AUTH PLAIN LOGIN CRAM-MD5 DIGEST-MD5
Net::SMTPS=GLOB(0x56154bf1cf60)<<< 250-STARTTLS
Net::SMTPS=GLOB(0x56154bf1cf60)<<< 250-BURL imap
Net::SMTPS=GLOB(0x56154bf1cf60)<<< 250-CHUNKING
Net::SMTPS=GLOB(0x56154bf1cf60)<<< 250 HELP
Net::SMTPS=GLOB(0x56154bf1cf60)>>> STARTTLS
Net::SMTPS=GLOB(0x56154bf1cf60)<<< 220 Ready to start TLS
Net::SMTPS=GLOB(0x56154bf1cf60)>>> EHLO localhost.localdomain
Net::SMTPS=GLOB(0x56154bf1cf60)<<< 250-smtp.strato.de greets 89.245.1.55
Net::SMTPS=GLOB(0x56154bf1cf60)<<< 250-ENHANCEDSTATUSCODES
Net::SMTPS=GLOB(0x56154bf1cf60)<<< 250-PIPELINING
Net::SMTPS=GLOB(0x56154bf1cf60)<<< 250-8BITMIME
Net::SMTPS=GLOB(0x56154bf1cf60)<<< 250-DELIVERBY
Net::SMTPS=GLOB(0x56154bf1cf60)<<< 250-SIZE 104857600
Net::SMTPS=GLOB(0x56154bf1cf60)<<< 250-AUTH PLAIN LOGIN CRAM-MD5 DIGEST-MD5
Net::SMTPS=GLOB(0x56154bf1cf60)<<< 250-REQUIRETLS
Net::SMTPS=GLOB(0x56154bf1cf60)<<< 250-BURL imap
Net::SMTPS=GLOB(0x56154bf1cf60)<<< 250-CHUNKING
Net::SMTPS=GLOB(0x56154bf1cf60)<<< 250 HELP
Net::SMTPS=GLOB(0x56154bf1cf60)>>> AUTH-my favorite: LOGIN
Net::SMTPS=GLOB(0x56154bf1cf60)>>> AUTH-server offerred: PLAIN LOGIN CRAM-MD5 DIGEST-MD5
Net::SMTPS=GLOB(0x56154bf1cf60)>>> AUTH-negotiated: LOGIN
cannot do mail auth at ./FHEM/sendEmail.pm line 18.