This has happened to me a couple of times over the past ~2 years. I'm on
a *nix based mail system operated by campus IT, not gmail.
On 9/15/2016 9:16 AM, Eric Hellman wrote:
> Have others been having difficulty staying subscribed? It seems gmail doesn't like the CLIR listserv.
>> - The first error was reported on 2016-09-09.
>> - Since then, a total of 10 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 <https://support.google.com/mail/?p=IPv6AuthError> for more information 550
>> 5.7.1 . g16... (23 bytes suppressed)
> Eric Hellman
> President, Free Ebook Foundation
> Founder, Unglue.it <http://unglue.it/> https://unglue.it/ <https://unglue.it/>
> https://go-to-hellman.blogspot.com/ <https://go-to-hellman.blogspot.com/>
> twitter: @gluejar