Simon et al;
After reading your post(s) regarding "This account does not exist" message I do not see where anyone had set the SSL settings for the Portal.
SSL is portal independant you must turn it on per Portal like so:

Setting Portal SSL Settings

How to set the SSL settings for an individual portal.

1. Navigate to Host > Portals.

2. Click the Edit button beside the title of the required portal. This opens the Edit Portals page.

3. Maximize the Advanced Settings section.

4. Maximize the SSL Settings section.

5. OPTIONAL. At SSL Enabled?, check the check box if an SSL Certificate has been installed for this

portal.

6. OPTIONAL. At SSL Enforced? check the check box if pages which are not marked as Secure are not

accessible with SSL (HTTPS).

7. OPTIONAL. In the SSL URL text box, enter a URL which will be used for secure connections for this

portal. This is only required if the SSL Certificate does not match your standard URL. E.g. www.secure.

domain.com

8. OPTIONAL. In the Standard URL text box, enter your standard portal URL for non-secure connections.

9. Click the Update link.