Bad reputation of email server at AOL

I use Launchpad with an email address from AOL. However, all emails from Launchpad (e.g. password reset, PPA upload confirmations) take a considerable amount of time before arriving in my inbox. The issue seems to be that the reputation of the sending server (in my case adelie.canonical.com [91.189.90.139]) at AOL is pretty bad (according to http://postmaster.aol.com/cgi-bin/plugh/check_ip.pl ) and thus, emails are not delivered on the first try.
From what I read at http://postmaster.aol.com , there are multiple possible causes of this and there are multiple ways to improve the situation (one might be to apply for a whitelist entry).

The time I have to wait for an email differs and can reach up to 6 hours. It would be great if someone could look into this.