Follow up from T255046: Request creation of "chat" VPS project (for a Mattermost instance)

It seems mails from this node is not reaching outside

It looks like the emails may be malformed? Google is rejecting delivery. (Ignore the ipv6 connectivity error in the log output. That's not the real problem.)

$ ssh root@out01.cloudinfra.eqiad.wmflabs
$ cd /var/log/exim4
$ zgrep 1k72eA-0001q6-J1 mainlog.2.gz
2020-08-15 20:19:22 1k72eA-0001q6-J1 <= <> H=chat-mattermost01.chat.eqiad1.wikimedia.cloud (chat-mattermost01.chat.eqiad.wmflabs) [172.16.1.207]:59870 I=[172.16.1.239]:25 P=esmtp S=5351
2020-08-15 20:19:22 1k72eA-0001q6-J1 H=gmail-smtp-in.l.google.com [2607:f8b0:400d:c03::1b] Network is unreachable
2020-08-15 20:19:23 1k72eA-0001q6-J1 ** ladsgroup@gmail.com R=dnslookup_unsigned T=remote_smtp_unsigned H=gmail-smtp-in.l.google.com [209.85.201.26] I=[172.16.1.239] X=TLS1.2:ECDHE_ECDSA_CHACHA20_POLY1305:256 CV=yes DN="C=US,ST=California,L=Mountain View,O=Google LLC,CN=mx.google.com": SMTP error from remote mail server after end of data: 550-5.7.1 [185.15.56.18      14] Messages missing a valid address in From:\n550 5.7.1 header, or having no From: header, are not accepted. q15si7590040qvf.69 - gsmtp
2020-08-15 20:19:23 1k72eA-0001q6-J1 ladsgroup@gmail.com: error ignored
2020-08-15 20:19:23 1k72eA-0001q6-J1 Completed