dastardly microsoft

So we're learning to do internet coding and learning, if we don't know already, that different browsers sometimes render code in unexpected ways. yesterday i had an experience that made me suspicious that microsoft may be unfairly using this fact. i have an msn email account. sometime ago i began having trouble logging in. on my first log-in attempt, i would be told my password was wrong; invariably, however, i would be logged in on my second attempt. after putting up with this bug for too long, i called msn help yesterday, only to be told that the problem was with firefox. firefox browsers now must be logged in to msn email twice before a connection is made. they told me i should use the latest version of explorer, but the latest version of explorer isn't made for macs. is microsoft creating bugs preventing smooth usage of msn email with macs and with firefox?