Unable to access dashboard of SSL subdomain – keeps redirecting to parent domain

Sites hosted on Bluehost. Sub-domain site was working fine before wildcard SSL certificate was installed. Parent domain was parked and redirected to the main domain on the hosting account (a separate domain).

Installation of the SSL certificate caused both the subdomain and parent domain to redirect to the main domain. The parent domain was unparked and made an addon domain. Site from the main domain was installed on the parent domain. .htaccess file updated to force https. Parent domain now works fine (public and logged in pages).

At this point the subdomain did not work at all – all pages redirected to parent domain. Eventually Bluehost advised that for wildcard SSL to work the subdomain the subdomain home directory had to be a sub directory of the parent domain. Files were moved, subdomain record recreated to point to the new file location and the .htaccess files updated.

Now the sudomain site displays the public pages fine (forcing https), but when you login you are redirected to the login page on the parent site. If you then go back to the subdomain, the admin bar displays, indicating that the login was successful. However, any attempt to click on a link in the admin bar, or type an admin page URL directly results in being redirected to the paren site login page again.

Plugins have been disabled – no change.
WordPress and theme have not changed since the site was working on http (before the SSL certificate was installed). I have followed all the steps in the codex, and checked some old threads here in the forum, but no joy.

For reference, the sites are courses.jojoebi.com and jojoebi.com. Trying to access any of the admin pages on the courses site redirects to https://jojoebi.com/login-2/?redirect_to=https%3A%2F%2Fcourses.jojoebi.com%2Fwp-admin%2F&reauth=1

Any ideas how to fix this?