Prior to resetting your password, please note that the email and password fields are case sensitive. If you have included any capital letters in your email you may want to try re-entering your email, case specifically as you did when you created your account, prior to resetting your password as your password may not be the issue.
If you have forgotten your password you can easily reset it.
On the login screen select the forgotten password link under the red sign in button.
On the next screen enter your email address and click the green request forgotten password button.
This will trigger a reset email to be sent to the specified email address.
Please ensure you check your junk & spam folders for the reset email.