There are a few possible reasons why you might see the "Incorrect Email or Password" error when you are trying to sign in to the web interface and access your account.
Either your email or password is incorrect. Note that the password is case sensitive, and that you need to provide the exact email address associated with your account. If the email address associated with your account is email@example.com, then firstname.lastname@example.org will fail, and so will email@example.com.
You have just changed your password and did not give the password change process time enough to complete.
You have enabled Two Factor Authorization (2FA) on your account and you are not correctly adding the token to the end of your password. If you've enabled 2FA, remember that you must (1) request and receive a token, and (2) add it to the end of your password. For example, if your password is "password" and you receive the token "12345", then you would enter
password12345in the password field of the web interface login form. To make things harder for the bad guys, no mention of 2FA-related problems are made in error messages. For more information, see this page.
The account has been closed.
If you are still unable to access your account or you have any questions, contact us at firstname.lastname@example.org, writing from the email address associated with your account.