I'm having the very strange problem in my local dev environment, which somewhat mirrors a similar problem with my live config.
on my windows dev environment, I can log-in to my drupal installation just fine when accessing it using:
HOWEVER, if I try to access it using:
I cannot log-in. If I type the wrong password, then I get a warning box. But if I type in the right password, then nothing happens. it seems like it just does a reload of the home page. Nothing shows up in the logs, either.
It must be a config problem, but I have no idea what or where.
BTW, I have a similar problem with my site hosted on Site5. However, on site5 if I switch from php5 to php4, I can log-in just fine. Switching to php4 on my local dev environment doesn't help.