Client is not able to use Family Portal after previously being able to sign in with no issue. Has tried using incognito window, and the links sent directly to client with no successful sign in's after original set up.
It looks like the Client and Client Contact are using the same email address.
According to our Zendesk article, you cannot use the same email address for multiple accounts (for example, a client and a contact cannot use the same email address for accessing the Family Portal). Each email address can only be tied to one profile or else it causes issues with Family Portal.
Change the Client's email address to something different and then resend an invite.