I came across this interesting known issue for Gmail when I was poking around last night trying to figure out another problem.
Google's web email may not load in Google's browser. Use Firefox instead.
A rather interesting (and rather amusing) issue that Gmail won’t load in Chrome. I’ve been using Chrome on and off since it came out (more so now that I have a computer that has enough RAM for it, Chrome seems to like using lots of RAM), and I used to have the issue they’re describing happen to me quite often. It hasn’t happened for months now, so I’m assuming it’s a historical issue with old versions of Chrome.
Source (though there’s no guarantee it’s still there anymore): Gmail Known Issues – Gmail Help