UPDATE and success: several very helpful readers helped me debug the issue—many thanks.
Not only should GMail (or any other mail server) not mark mail as junk, it also does SPF=PASS, which is an improvement over before where it was neither yeah nor nay.
This is for the nerds out there like me who run their own mail server—the desired thing to see in the headers is this:
Received-SPF: pass (google.com: domain of ****@diglloyd.com designates 220.127.116.11 as permitted sender) client-ip=18.104.22.168
The TXT record (SPF) turned out to be trivial since I use only one IP for email:
diglloyd.com v=spf1 ip4:22.214.171.124 -all
I always reply to courteous and appropriate emails.
In the past week, I’ve responded to half a dozen readers asking why no reply. There my response sits in the GMail JUNK folder, which all of these readers confirmed. I’ve had to resort to multiple different email accounts in order to get through (e.g., diglloyd.com, me.com, etc).
Please check your junk folder if you do not receive a reply, GMail or otherwise (Earthlink.net is the very worst of all).
This is a behavioral change apparently brought on by something over at Google. As far as I can determine, I have all my DNS and DNS-related records correct. I have no idea how I could get Google to keep its aggressive algorithm from junking my messages.
Invalid email address at PayPal
Sometimes readers/subscribers use bad emails even when subscribing, not checking if the email at PayPal is even valid. I have no way to contact these users—none at all since PayPal does not supply that kind of contact info in most cases—so I am helpless in that situation.
Email address that just doesn’t work
Sometimes the email is at a server that doesn’t even function, sometimes the server says “email box full”, etc. Example:
The following message could not be delivered to ****@earthling.net at host earthling.net (126.96.36.199) because the host is not accepting mail.
The following message could not be delivered to ******@gmx.info at host gmx.info (188.8.131.52) because the host is not accepting mail. 554-gmx.net (mxgmx116) Nemesis ESMTP Service not available
After 3 days the following message could not be delivered to *****@suddenlink.net at host suddenlink.net (184.108.40.206). The last attempt to send this message failed because the message was temporarily rejected. 421 dalifep02.suddenlink.net connection refused from [220.127.116.11]
DM3NAM03FT018.mail.protection.outlook.com rejected your message to the following e-mail addresses: *******@autonation.mail.onmicrosoft.com DM3NAM03FT018.mail.protection.outlook.com gave this error: Hop count exceeded - possible mail loop
The following message could not be delivered to ****@optonline.net at host optonline.net (18.104.22.168) because the sender address was rejected. 550 5.7.1 Unacceptable hostname 173-164-178-42-SFBA.hfc.comcastbusiness.net from host 22.214.171.124 : denied - 01 Reporting-MTA: dns; llc4.com
This last example is annoying: optonline.net clearly recognizes DNS as llc4.com (which is also diglloyd.com), yet it refuses the email. I’ve put in place DNS records, but either I’ve got it wrong, or some email servers do not check things like TXT records for email servers, e.g.:
smtp.diglloyd.com v=spf1 +mx +a -all
It is my understanding that this TXT record should make most mail servers happy. Maybe someone network nerd out there can help me figure this out. It’s not like smtp.diglloyd.com is unavailable on DNS:
diglloyd-iMac:DIGLLOYD lloyd$ ping smtp.diglloyd.com PING smtp.diglloyd.com (126.96.36.199): 56 data bytes