New user cannot create zoho account to join my crm. "Invalid Request" error

New user cannot create zoho account to join my crm. "Invalid Request" error

New user is trying to create zoho account to join my crm by clicking on link in email invite and by manually copying and pasting link into browser which brings up this "Invalid Request" error?  Have tried different browsers etc, and same error populates and this user isn't able to create zoho account and join crm??