This usually means the user is attempting to register and sign in with a disposable email address. To avoid fraud and ensure that the emails in your CRM belong to real people that can be communicated with, Pico accounts and paid membership can only be associated with permanent email addresses. Users will need to enter a valid permanent email address to continue.
If you believe that Pico is improperly flagging valid email domains, please reach out to us at [email protected]