Unfortunately, the advice of all three people didn't help. Curiously, if I change the case from -layer=> 'tls', to -layer=> 'TLS', then the error messages change entirely: 

  ...
  Net::SMTPS=GLOB(...etc...)>>>> EHLO localhost.localdomain
  Net::SMTPS=GLOB(...etc...)>>>> 250-smtp.gmail.com at your service ..
+.
  Net::SMTPS=GLOB(...etc...)>>>> 250-SIZE 35882577
  Net::SMTPS=GLOB(...etc...)>>>> 250-8BITMIME
  Net::SMTPS=GLOB(...etc...)>>>> 250-STARTTLS
  Net::SMTPS=GLOB(...etc...)>>>> 250-ENHANCEDSTATUSCODES
  Net::SMTPS=GLOB(...etc...)>>>> 250-PIPELINING
  Net::SMTPS=GLOB(...etc...)>>>> 250-CHUNKING
  Net::SMTPS=GLOB(...etc...)>>>> 250 SMTPUTF8
  Net::SMTPS=GLOB(...etc...)>>>> AUTH LOGIN
  Net::SMTPS=GLOB(...etc...)>>>> 530 5.7.0 Must issue a STARTTLS comma
+nd first ... Authentication (SMTP) failed

[download]

but note that one of the messages confirmed STARTTLS already.

In reply to Re^2: Problem sending Gmail from Widows 10 by haprst
in thread Problem sending Gmail from Widows 10 by haprst

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