I have lots of wordpress installations under my belt but a have two installations on another hosting company. Both of these struggle to login using firefox (mac). I will enter my wordpress admin username and password and the window will refresh clearing the login boxes. I've definitely entered the correct login details. I've since found that once i've tried to login once, if I manually type in the toolbar http://www.site.com/wp-admin/ and hit enter i get into my dashboard. Is there any reason for this? or has anybody run into the same issue?