Issue #11628 has been reported by Robert Pankowecki.

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Bug #11628: Net::SMTPServerBusy is not behaving according to documentation
https://bugs.ruby-lang.org/issues/11628

* Author: Robert Pankowecki
* Status: Open
* Priority: Normal
* Assignee: 
* ruby -v: ruby 2.2.3p173 (2015-08-18 revision 51636) [x86_64-linux]
* Backport: 2.0.0: UNKNOWN, 2.1: UNKNOWN, 2.2: UNKNOWN
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The documentation for Net::SMTPServerBusy says _Represents SMTP error code 420 or 450, a temporary error_ (http://ruby-doc.org/stdlib-2.2.0/libdoc/net/smtp/rdoc/Net/SMTPServerBusy.html)

However the code for that is:

~~~
      def exception_class
        case @status
        when /\A4/  then SMTPServerBusy
        when /\A50/ then SMTPSyntaxError
        when /\A53/ then SMTPAuthenticationError
        when /\A5/  then SMTPFatalError
        else             SMTPUnknownError
        end
      end
~~~

so it actually represents any error code starting with 4, including such as: `Net::SMTPServerBusy: 401 4.1.3 Bad recipient address syntax`.

It doesn't help that different pages in internet list different error codes:

* http://www.serversmtp.com/en/smtp-error
* http://www.greenend.org.uk/rjk/tech/smtpreplies.html






-- 
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