Mysterious Authentication Problem on Microsoft Environment

This is not the first time. I just changed my password (a practice I do every couple months or so) and couple of days later, I have problems logging in to my account! Can't go on my Exchange email, nor even access any system that uses the domain account. Very mysterious indeed.

I would end up calling helpdesk to reset my password as the first suspicion would be a typo in my new password. I'd check my network connections and everything is as normal as can be. It pings fine with the domain server as well, DNS resolves beautifully.. No problems there. Tried the OWA version of the email and still no luck either... So what else is left?

I called up helpdesk again asking for help to check whether my account was 'accidentally' disabled. But then 5-10minutes later, I tried login in and hey, it worked! I'm just dumbfounded. This will be forever a mystery to me. Intermittent network connection? I doubt it... My only suspicion left is the authentication server. Either its load is too high, or something else is disrupting the transaction and my packets were dropped somewhere along the way...