If you already had an Intuit account associated with a different email address  (e.g. because you had used TurboTax previously), you need to make sure you are not only using the link in your accountant's email (which contains a token) to access Intuit Link but also (very importantly) your email address in that invitation to log in.

If you still have problems logging in, you need to contact your accountant who will then diagnose the issue for you and provide you with further guidance.  This Community is only open to tax professionals and will not assist with consumer questions.