Login only works after resetting password

So, just a week ago I decided to set up my website and add a wordpress blog to it. It all went pretty well, and as I’d tried several installations of wordpress locally before taking this step, any minor bugs were easily solved.

However, now I find myself facing a very weird problem.

Every time I wish to login to the wp-admin area, even though I insert the correct username and password, it loads the same page again. And again. And again. But if I press the ‘Lost password?’ option and ask for it to send me the password once more(which is the one I entered just before), and then go back and try to login once more. It all works suddenly.

At least until I log off again.

I’ve tried to reset and change password through a million of ways, and nothing works.

Has anyone got any ideas as to what might be causing this?

Thank you.