To be clear, this is about the account, not the list. Your colleague either needs to do some housekeeping or purchase more space from the friendly folks at Google.

> On Sep 14, 2016, at 6:08 AM, Cowan, William G <[log in to unmask]> wrote:
> 
> Running out of space? See https://support.google.com/mail/answer/6374270?hl=en
> 
> 
> Will
> 
> 
> On 9/14/16, 09:03 , "Code for Libraries on behalf of Josh Wilson" <[log in to unmask] on behalf of [log in to unmask]> wrote:
> 
>    Hey all,
>    My colleague was unexpectedly booted from the Code4Lib list and received
>    the message below. She uses a work Gmail account so it doesn't seem
>    especially likely to be misconfigured. I didn't realize there were any
>    additional requirements for the new listserv, I wonder if this is affecting
>    others.
> 
>    Any thoughts on how to fix this?
> 
> 
>    * * *
> 
>    You  have been  automatically removed  from the  CODE4LIB list  (Code for
>    Libraries) as a result of repeated  delivery error reports from your mail
>    system. This decision was based  on the list's automatic error monitoring
>    policy and has  not been reviewed or otherwise confirmed  by a person. If
>    you receive  this message, then it  means that something is  wrong. While
>    you  are obviously  able  to  receive mail,  your  mail  system has  been
>    regularly reporting  that your account  did not  exist, or that  you were
>    otherwise permanently  unable to receive  mail. Here is  some information
>    that may assist you  or your local help desk in  determining the cause of
>    the problem:
> 
>    - The failing address is [redacted]
> 
>    - The first error was reported on 2016-09-08.
> 
>    - Since then, a total of 3 delivery errors have been received.
> 
>    - The last reported error was: 5.7.1 550-5.7.1
>    [2600:3c03::f03c:91ff:fe55:a961]  Our  system   has  detected  that  this
>    550-5.7.1 message  does not  meet IPv6  sending guidelines  regarding PTR
>    records   550-5.7.1   and   authentication.   Please   review   550-5.7.1
>    https://support.google.com/mail/?p=IPv6AuthError for more information 550
>    5.7.1 . s67... (24 bytes suppressed)
> 
>    Please do  not ignore  this message.  While you  can re-subscribe  to the
>    list,  it is  important  for you  to  report this  problem  to your  mail
>    administrator so that  it can be solved. This problem  is not specific to
>    the CODE4LIB list and may also  affect your private mail. This means that
>    you may have  lost some private mail  as well. Anyone trying  to write to
>    you during  the same time frame  might have received the  same errors for
>    the same reason.
> 
> 
>