Is it possible that AOL blocks someones ip from access webmail.aol.com

Yes it is possible.

It's possible, but I'd be surprised unless you were using your account to spam or send threats or something. So much crap is sent through email these days, you'd really have to make yourself a target.

Also, sometimes places will block an IP if they make too many failed log-in attempts over a short period of time. Maybe your password was phished?

Hi Old..

I created about 5 aol email accounts and after sending 300.. I was not able to access webmail.aol.com....

But from my ip .. I can...

Yeah, it sounds like the IP you sent all of those emails with was blocked. If you're going to spam using a public email service, maybe cycle proxies so you only send 150 from each one, each day. Find the access limit for each service and integrate it into whatever software or script you're using.