Survey invitations sent to a specific customer do not automatically log them in to their accounts.

for example

1) www.myodoo.com/survey/start/my-survey-1/31575e9c-33a2-4bcb-8fcd-66212ed1845a - returns 403 error

2) www.myodoo.com/survey/start/my-survey-1/31575e9c-33a2-4bcb-8fcd-66212ed1845a ?login=my@account.com -  also returns 403 error

If the customer logins to myodoo.com first, by simply clicking the 'sign in' button then 1) above does work. The browser evidently has enough information to automatically log the user in, how can this be done so that it is seamlessly done for the customer. (This is necessary if you want them to actually bother to engage with the survey.)