On Thu, 1 Apr 2021 22:29:53 +0000, "Bruce  Johnson"
<xxxxxx@Pharmacy.Arizona.EDU> ("Listmom") wrote:

>This was explicitly a conflict between my domain's spam appliance (a
>Barracuda Systems box) and what Simplelist is sending me; and
>shouldn’t affect anyone else (unless their email service is set to
>block ’Spoofed’ emails. Basically the list is sending the message to
>the list as the address of the sender, and our spam appliance sees my
>email address coming from a non-COP IP address and thinks it’s a
>spoofed address.

>This happened within the last month or two and we’re trying to figure
>out what changes we made to cause this.

If the device accesses off-site heuristics for decision-making, don't
assume that it's something you did; it may have been an update pushed
by Barracuda.

In any event, if you can't figure it out, you may have to turn on the
"Yahoo hack" for your address on the list...