There are three key areas to consider when troubleshooting registration problems. These are outlined below:
1 - Password Criteria not met
2 - They haven't accepted the terms & conditions
3 - The user already has a registered account for their email address
4 - The user is not registering with a valid email address
5 - The person is trying to login \ register and is not starting by clicking the questionnaire link.
1. Password Criteria not met
The most common reason that respondees have a problem with registration, is that they haven't met the password criteria when creating the password.Once you have entered a password that meets the criteria, and you have ticked the box to confirm the T&Cs and Privacy Policy - your screen should display as below, and you should be able to register.

If your password does not meet the criteria - the highlighted criteria that has not been met will be highlighted in red as per the image below. To continue reenter your password meeting all the requirements until they all turn green.

2. The Terms & Conditions have not been accepted.
3. The person already has a registered account for their email address
If the respondee attempts to register with an email address that they have a previously registered with, they will need to select 'Have an Account? They can then sign in to their existing account, rather than REGISTER. If they have forgotten the password for their existing account, they will need to select 'FORGOTTEN PASSWORD' from the SIGN IN page.

4. The user is not using a valid email address when registering.
The registration screen will not progress until a valid email address is entered.
A valid email address must be an email account the user has access to, in order to receive the validation notification and use the reset password function if required.
5. The user is trying to register without clicking on the questionnaire link.
If this occurs, this message will appear.
Ask the user to start first by clicking on the questionnaire link, then registering.
Once all the conditions on the Registration page have been met, the Registration button will activate.