I was dropped from the list earlier this week   - our campus HelpDesk has since gotten other faculty reporting that they are being dropped from listservs with similar error messages. 



- 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 . r30... (25 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.