In general, all users can easily log in to the website. Either by putting down account credentials in the empty fields Email and Password or pressing the Google authorization button.
If one of these methods is not working, you should check the other, and vice-versa.
The most repeated problem with authorization is the one you can see on the screenshot below. In this situation, try both options to authorize on the website.
Unless it helps, you can also reset your password by clicking "Forgot my password".