There are three primary things that cause delivery issues when sending mail to AOL:
- You're not whitelisted,
- Your bounce handling is broken, or you're not looking at bounces; or
- You're generating too many complaints or too many bounces.
You're not whitelisted
This is quite easy to fix. Go here, read the page, agree to the terms and fill out the form. AOL will then respond if they either accept or not your application. If they do, you're on track to be exempted from some of their basic spam filtering. This will resolve some of your issues, potential or actual. If they don't, see steps two and three below, as they're probably preventing you from getting whitelisted.
To get whitelisted, you need to make sure you're mailing from an IP address that is being used just for your mail. If you're small enough to share a sending IP address with other people sending mail, you're not really a sender. You're a customer of a sender. Whoever owns, maintains, or supports that IP address should be filling out the whitelist form on your behalf.
Your bounce handling is broken, or you're not looking at bounces. Every email AOL bounces back to you contains a URL linking you to more information. So if you don't know what's going on with your AOL delivery, you probably don't have access to this data, or aren't looking at it.
These URLs lead to pages that give you clear information about what's going on. AOL will tell you if your message is incorrectly formatted, if you have a URL specified in a way that only spammers use, if you're generating too many spam complaints and so on.
You're generating too many complaints or too many bounces.
If you get whitelisted, and are reading bounces correctly, and are still having blocking issues, then the information provided in bounces probably indicates that your mail is causing too many bounces or too many spam complaints. AOL (and many other ISPs) can tell how much of your attempted mail is undeliverable, and how many of your recipients report it as spam. These are important measures used by AOL (and others) to decide which mail gets through, and which mail gets bounced.
How to reduce your bounce rate: Collect the bounces with eMail Bounce handler and clean your lists. Indeed, don't attempt to remail bounced names. They're not going to magically go through next time, and your failed attempts will actively damage your email reputation. If you don't filter out bounces, your bounce rate will grow with each mailing, and you will quickly exceed AOL's spam-measuring bounce threshold. (Spam mail bounces at a high rate; spammers generally have very poor bounce handling. ISPs consider it a valid measure.) If you're doing this and still having this problem, then your signup/opt-in practices are broken, and they are resulting in too many invalid addresses being added to your list. It's making you look like a spammer.
How to reduce your spam complaint rate: Don't send mail to people who don't want it. Don't obtain lists from third parties. The people on those lists didn't opt-in to mail from you, and don't know who you are. Many of them will report your mail as spam. It doesn't matter if it's legal; it's just as legal for AOL to notice the high number of complaints and choose to block your mail. The most useful thing you can do is fix this. The most useless thing you can do is complain about it to the world at large. Don't tell the world you're not spamming and everybody's out to get you. As far as the recipients and receiving ISPs are concerned, you are sending spam.
Also, it's very important that you sign up for a feedback loop from AOL. This will provide you with copies of spam complaints brought against you by AOL users. You can (and should) ensure that these people are unsubscribed from your list. If you don't, you're not going to reduce spam complaints.