Can Login with FireFox but not IE

Are you running as localhost in the URL, or with 127.0.0.1, or as an actual https://www.yoursitehere.com?
TG

Update:
A recent security patch in IE will not allow cookies to be set from non-compliant RFC host names. That means IE will not accept cookies from host names with underscores. Here’s a link to a newsgroup article that explains the problem.
https://groups.google.com/groups?q=IE+cookies+underscore&hl=en&lr=lang_en&ie=UTF-8&selm=3cd7142b_6%40corp-goliath.newsgroups.com&rnum=4

I don’t even get an ‘atta-boy’ for figuring this out. What kind of “support” board is this? ??

I’m afraid non-compliant RFC host names are not the only cause for this problem. My host name uses no unusual characters, but logging into my blog is impossible with IE. Does anyone have any other ideas? thanks!