Won't Log In

I can’t log in through /wp-admin/ or /wp-login.php

I enter my username / pass and it just redirects me to the Login page. No error message or anything. I see in the URL : /wp-login.php?redirect_to=https%3A%2F%2Fwww.mydomain.com%2Fwp-admin%2F&reauth=1 but this just shows the login page again.

I have heard it could be a session issue, but not sure how this can be corrected.