I checked your account and I see you deleted the domain from your account and added it again. While that’s a common troubleshooting step, it’s rarely helpful and has some nasty side effects.
One of those side effects is that it changes the directory of your website from htdocs to motive-tld.com/htdocs. But the latter directory does not exist, which is why you get the 403 error.
To fix this, please move the htdocs directory to the right location:
Note that you’ll still need to add a DNS records for the www subdomain if you want that to work.