J,
Our group "officially" tells members not to use an aol address for
Groups.io. Most of the aol members have created gmail accounts by
this point, but a couple of them continue to use aol. They're missing
messages (as can be seen from their email delivery logs) but they
don't seem to care.
According to what Mark said (much earlier), he suspects that refusing delivery of messages from a mailing list is AOL's way of "punishing" email list services that don't act upon FBL reports. That's why he resumed unsubscribing members in response to those reports.
The problem is that the AOLs refusal to deliver does not seem to be tied to a specific member or a specific group, but appears to arbitrarily affect all messages from Groups.io. It is as if the probability that a message will be refused is in some sense proportional to the "spammy-ness" reputation of the list service overall.
I don't know if the situation has improved, but Mark complained at the time that he was unable to get any guidance from AOL as to how they expect him to interpret and respond to the FBL reports, and what the consequences are if he does or doesn't.
Shal