AOL rejects mail

[rkacker]

Hello.

We people at mbhs.edu just changed our ISP. We updated all out nameservers for the new 
MX IP,and mail seems to be working for certain sites, but not all.  AOL, erols, 
compuserve seem to be rejecting our mail.  I'm not certain what is wrong./
Has anyone had this type of problem before?

Thanks,
Ravi