We've been struggling with a situation where only certain emails are not arriving at our server. The email clients are returning "unable to deliver" but nothing looks odd about the header.
In every case the errant email is from a large institution -- universities, large law firms, and government entities. Mail from gMail, AOL, and individual accounts at an ISP or private mail server comes through promptly.
We are wondering if an incremental ICANN table got screwed up and the large institutions, that presumably are their own ISPs, have faulty tables until they do a full resynchronization -- which in these tight money days may be a long while in coming.
A) Does this hypothesis make sense to you?
B) Apart from changing our NS1 & NS2 to something goofy and then changing back to the original dot addresses, is there a way to simply ask that the existing NS1 & NS2 be included in the next incremental tables ICANN publishes?