Gmail email blocking is off the rails (again)

[Matthew Pounsett <matt () conundrum com>]

For some reason Gmail has started blocking mailman administrative emails to
someone who's an admin on a list I host.  Their SMTP 552 error message
points to <https://support.google.com/mail/?p=BlockedMessage>, which
implies the "problem" is the URLs in the email, but is otherwise completely
unhelpful.

If anyone here has any pull with Gmail postmasters, could you please
suggest to them that they whitelist messages that are as consistent and
well-known as mailman's admin and moderator messages?