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.