Here is the entire output, login looks fine.

Net::SMTP::_SSL>>> Net::SMTP::_SSL
Net::SMTP::_SSL>>>   IO::Socket::SSL(2.040)
Net::SMTP::_SSL>>>     IO::Socket::IP(0.38)
Net::SMTP::_SSL>>>       IO::Socket(1.38)
Net::SMTP::_SSL>>>         IO::Handle(1.36)
Net::SMTP::_SSL>>>           Exporter(5.72)
Net::SMTP::_SSL>>>   Net::SMTP(3.10)
Net::SMTP::_SSL>>>     Net::Cmd(3.10)
Net::SMTP::_SSL=GLOB(0x1875d54)<<< 220 gmx.com (mrgmx105) Nemesis ESMT
+P Service ready
Net::SMTP::_SSL=GLOB(0x1875d54)>>> EHLO Rob.nl
Net::SMTP::_SSL=GLOB(0x1875d54)<<< 250-gmx.com Hello Rob.nl [83.82.13.
+137]
Net::SMTP::_SSL=GLOB(0x1875d54)<<< 250-8BITMIME
Net::SMTP::_SSL=GLOB(0x1875d54)<<< 250-AUTH LOGIN PLAIN
Net::SMTP::_SSL=GLOB(0x1875d54)<<< 250 SIZE 69920427
Net::SMTP::_SSL=GLOB(0x1875d54)>>> AUTH LOGIN
Net::SMTP::_SSL=GLOB(0x1875d54)<<< 334 VXNlcsm5hbWU6
Net::SMTP::_SSL=GLOB(0x1875d54)<<< (decoded) Username:
Net::SMTP::_SSL=GLOB(0x1875d54)>>> (decoded) someone@example.com
Net::SMTP::_SSL=GLOB(0x1875d54)>>> <redacted>
Net::SMTP::_SSL=GLOB(0x1875d54)<<< 334 <redacted>
Net::SMTP::_SSL=GLOB(0x1875d54)<<< (decoded) Password:
Net::SMTP::_SSL=GLOB(0x1875d54)>>> (decoded) <redacted>
Net::SMTP::_SSL=GLOB(0x1875d54)>>> <redacted>
Net::SMTP::_SSL=GLOB(0x1875d54)<<< 235 Authentication succeeded
Net::SMTP::_SSL=GLOB(0x1875d54)>>> MAIL FROM:<someone@example.com>
Net::SMTP::_SSL=GLOB(0x1875d54)<<< 250 Requested mail action okay, com
+pleted
Net::SMTP::_SSL=GLOB(0x1875d54)>>> RCPT TO:<anyone@example.com>
Net::SMTP::_SSL=GLOB(0x1875d54)<<< 250 OK
Net::SMTP::_SSL=GLOB(0x1875d54)>>> DATA
Net::SMTP::_SSL=GLOB(0x1875d54)<<< 354 Start mail input; end with <CRL
+F>.<CRLF>
Net::SMTP::_SSL=GLOB(0x1875d54)>>> Hi amdy
Net::SMTP::_SSL=GLOB(0x1875d54)>>> .
Net::SMTP::_SSL=GLOB(0x1875d54)<<< 554-Transaction failed
Net::SMTP::_SSL=GLOB(0x1875d54)<<< 554 Unauthorized sender address.
Net::SMTP::_SSL=GLOB(0x1875d54)>>> QUIT
Net::SMTP::_SSL=GLOB(0x1875d54)<<< 221 gmx.com Service closing transmi
+ssion channel
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