We upgraded our install to the 2019 Week 1 version last week and set up the
cluster.mailers key; things seemed to be working fine, but I’ve started getting reports of users missing e-mails about tasks that they’re CC’d on.
I looked up one of the affected messages; if I run
./bin/mail show-outbound --id 993399 it shows up as “sent”, but when I look at it in Sendgrid it was only sent to void-recipient@ourdomain and didn’t have any of the CC’s. It never reached the user’s inbox.
We exclusively use Sendgrid for mail sending and cannot change that.
There is nothing in the daemon log.
I was able to reproduce this issue by verifying that
echo "this is a test" | ./bin/mail send-test --to $USERNAME --subject 'test 1'
echo "this is a test" | ./bin/mail send-test --cc $USERNAME --subject 'test 2'
is never delivered