Hi @Nicole_Paull, thanks for reaching out!
In this case, it’s possible that the Organization requires members to login using their G Suite account (Google SSO) or an specific identity provider: https://asana.com/guide/help/premium/authentication
If the Organization Admins have made this change, any passwords associated to your clients Asana account will no longer work and they will be required to use Google SSO or SAML.
Unfortunately I’m not able to confirm weather they have any of this settings enabled on their account as I don’t have the tools in the forum. You can recommend them to contact our support team and we will be able to confirm: How to contact our Support Team ✉
I hope this helps! 