I wrote an email to travel@torproject.org, which worked a few days ago, but now eugeni informed me it couldn't deliver to gmail: > This is the mail system at host eugeni.torproject.org. > > I'm sorry to have to inform you that your message could not > be delivered to one or more recipients. It's attached below. > > For further assistance, please send mail to postmaster. > > If you do so, please include this problem report. You can > delete your own text from the attached returned message. > > The mail system > > <<handle>@gmail.com>: host > gmail-smtp-in.l.google.com[2a00:1450:400c:c0c::1a] said: 550-5.7.26 This > mail has been blocked because the sender is unauthenticated. 550-5.7.26 > Gmail requires all senders to authenticate with either SPF or DKIM. > 550-5.7.26 550-5.7.26 Authentication results: 550-5.7.26 DKIM = did not > pass 550-5.7.26 SPF [<domain>] with ip: > [<ip> 550-5.7.26 8] = did not pass 550-5.7.26 > 550-5.7.26 For instructions on setting up authentication, go to 550 5.7.26 > https://support.google.com/mail/answer/81126#authentication > g7-20020a05600c4c8700b004107664bbe8si4522016wmp.61 - gsmtp (in reply to end > of DATA command) > ... At the same time, there was a CC directly to gmail from my own mailserver, which gmail accepted: > postfix/smtp[3961572]: F067B38802FE: to=<<handle>@gmail.com>, relay=gmail-smtp-in.l.google.com[<ip>]:25, delay=0.97, delays=0.13/0.01/0.41/0.43, dsn=2.0.0, status=sent (250 2.0.0 OK 1707803587 c8-20020adffb48000000b0033add90c729si3955987wrs.862 - gsmtp)