In <list-892602@2rosenthals.com>, on 07/16/20
    at 01:04 PM, "Massimo S." <ecs-isp@2rosenthals.com> said:

Hi,

i only use theese as RBLs:

dbl.spamhaus.org
sbl-xbl.spamhaus.org

maybe your ISP SMTP servers go often or sometimes, dunno, into black
lists

More from the multi-verse.  As someone that who gets paid to supply mail
services to clients, you must know RBLs are not the only tools that ISPs
use to determine whether or not to bounce emails.  There's Astero,
VladeSecure, Barracuda and many more.   They all have different criteria
for bouncing mail and the criteria changes over time.  There are times I
think the cure is worse than the disease.

I've had it happen to me.  In one interesting, for lack of a better word,
case an email would go through to the scoug-help mailing list at scoug.com
unless it contained a URL in the message body.  The issue went away after
a few days, so I have to assume the spam gateway that caused the bounce
fixed their broken rules.

My point is you can't be naive when looking for the cause of email
bounces.

I'm somewhat surprised you let the issue go unresolved for this long.

IAC, I will review your responses to the ticket and see how well you were
able to follow my instructions.

Steven