Did not receive issue #1411. Yes, I checked the junk folder. I also checked the mail logs for anything from tidbits that wasn’t from tidbits-talk.
Can someone tell me what the From and From: headers are on the latest issue? (Yes, From and From: are different 
SendGrid claims it was delivered to your ISP.
This is the only From header in the source that I see:
From: TidBITS <support@tidbits.com>
The “From” header would only be in a recipient’s email, and the addressed used there (often a bounce specific address) is the one that would be logged on my mail server.
Do you know the IP address of the machine sending the weekly issue? there is nothing on 2018/04/03 that seems to match. I have:
18:12:13 mail postfix/smtpd[71424]: 40FTzx3GZrzbRTr: permit: DATA from mail.tidbits.com[173.255.250.214]: action=permit for Data command=DATA ; from=<tidbits-talk-bounces@tidbits.com> to=<kremels@kreme.com> proto=ESMTP helo=<mail.tidbits.com>
But that’s a TBT post, not the issue.
there is also
18:21:47 mail postfix/smtpd[21800]: 40FVBz5txCzbRTr: permit: DATA from o3.lv30n.shared.sendgrid.net[167.89.100.226]: action=permit for Data command=DATA ; from=<bounces+6644078-b1c8-kremels=kreme.com@send.tidbits.com> to=<kremels@kreme.com> proto=ESMTP helo=<o3.lv30n.shared.sendgrid.net>
but the time codes don’t match at all. I’ll check for that message ID and see if I can track down what happened to that message.Probably it was tagged as spam and my list account has a very low threshold for discarding spam.
I found it in the mail backups. Your server’s UTC isn’t actual UTC dos I was an hour off in my logs. It scored a SpamAssassin Score of 5.4.
For accounts at our level ($20 per month for 100,000 messages, plus $10 per month per 10,000 contacts), SendGrid sends our email from a shared pool of IP addresses. I’ve seen at least 3 so far. Unfortunately because of that, other senders with worse reputations than ours can cause those IPs to end up on RBLs.
We could bump up to the $80 per month for 100,000 messages account and get a dedicated IP number. I’ll have to see how deliverability goes for the first few weeks.