Our website uses Google's reCAPTCHA to help to secure accounts - this is displayed as an "I'm not a robot" check box on the "Sign In", "SIgn Up" and "Reset Password" forms:
Login Page ReCaptcha
Password Reset Recaptcha
You cannot click the "Log In" or "Request" buttons until you've ticked the "I'm not a robot" check box and completed any puzzle that then appears.
If you don't see the "I'm not a robot" check box, check connections to Google aren't blocked (as is the case from China where you will need to use a VPN to get around this) and that you don't have any ad-blockers installed and active in your web browser which may interfere.
If the problem persists after you've consider the above suggestions, try in another web browser:
If you DO see and have ticked the "I'm not a robot" check box but still can't click the "Login" button - are you using Firefox browser with KeePass and the KeeFox Firefox add-in? If so, don't use the KeeFox add-in to auto-complete the email address and password as the data entered isn't seen by the page so the "Login" button remains unavailable as though you hadn't entered this data.